JP6042844B2 - Method and apparatus for measuring tire ground contact characteristics - Google Patents

Description

  The present invention relates to a method and an apparatus for measuring contact characteristics of a tire, and more specifically, a measuring method and an apparatus for measuring at least the contact pressure, width direction shear stress and circumferential direction shear stress of a rolling tire, By measuring the ground contact characteristics of tires at various speeds, camber angles and slip angles with high efficiency, high accuracy and high reproducibility, for example, quantitative determination of the ground contact state with the tire road surface during cornering and acceleration / deceleration In particular, the present invention relates to a measurement method and a measurement apparatus for tire contact pressure characteristics, which can be easily obtained with high resolution and can also provide tire contact characteristics during high-speed running.

  Conventionally, as a method of measuring contact characteristics such as tire contact pressure, width direction shear stress and circumferential direction shear stress during rolling, for example, a three-component force sensor capable of measuring these is embedded in a test road surface, There is a method of measuring the ground contact characteristics of a tire at the moment of passing over the three-component force sensor by passing the sensor.

  However, in the above method, since the vehicle is steered and passed through a three-component force sensor embedded in the test road surface, it is affected by external factors such as air resistance and unevenness of the test road surface. It is difficult to reproduce the measurement. In addition, from the viewpoint of sensor durability and vehicle controllability, this method cannot obtain the ground contact characteristics of the tire when the vehicle is traveling at a high speed or when a large input is applied, and when cornering or acceleration / deceleration. There's a problem.

  Further, in this method, since only data of a portion of the tire contact surface that has passed over the three-component force sensor can be obtained in one test, a distribution of the contact characteristics over the entire contact surface of the tire is obtained. Therefore, it is necessary to repeatedly perform the test while shifting the passing position, which is not efficient. Furthermore, since each test is large, there is a problem in that a large amount of measurement result data cannot be secured and the contact area of the tire cannot be clearly expressed with high resolution.

  Aside from the above method, there is a method of measuring a contact pressure by bringing a tire as a measurement object into contact with a drum. A tire tread pattern measuring device comprising: a tire pressing plate having a tire pressing plate attached between a tire and a drum so as to be movable in a drum axial direction; and a pressure-sensitive sensor attached to a tire contact surface of the tire pressing plate. However, due to the durability of the pressure-sensitive paper used, there is a problem that it is impossible to measure at high-speed rotation. Since it is only the contact pressure, the widthwise shear stress and the circumferential shear stress of the rolling tire cannot be measured.

Japanese Utility Model Publication No. 58-169546

  In view of the above problems, the present invention measures the ground contact characteristics of tires at various speeds, camber angles and slip angles with high efficiency, high accuracy, and high reproducibility, so that cornering, acceleration / deceleration, etc. Provided is a method and an apparatus for measuring the contact pressure characteristic of a tire, which can quantitatively and easily obtain the contact state with the road surface of the tire and which can also measure the contact characteristic of the tire during high speed running For the purpose.

The gist configuration of the present invention for solving the above problems is as follows.
The method for measuring the contact characteristics of a tire according to the present invention is a method for measuring the contact characteristics of a rolling tire, and includes at least measuring means capable of measuring the contact pressure, width direction shear stress and circumferential direction shear stress of the tire. In a state where only one of the embedded rotating drums that can be driven to rotate is brought into contact with a tire as a measurement target to which a required camber angle and slip angle are given, and the rotating drum and the tire are rotated together. , By simultaneously measuring at least the contact pressure of the tire, the width direction shear stress and the circumferential direction shear stress, while displacing the tire at a constant speed in the direction of the rotation axis of the rotation drum, the contact area of the tire with the rotation drum It is characterized in that a ground pressure distribution, a width direction shear stress distribution and a circumferential direction shear stress distribution are obtained.

  In the above, “required camber angle and slip angle” includes 0 °. In the above description, the rotational speed of the tire and the rotational speed of the rotary drum may be different.

  Preferably, the measurement unit is a three-component force sensor capable of measuring a tire contact pressure, a width direction shear stress, and a circumferential direction shear stress. Further, the tire is relatively displaced with a constant pitch width of 1 mm or more and 4 mm or less in the rotation axis direction of the rotary drum.

The apparatus for measuring contact characteristics of a tire according to the present invention includes a rotating drum in which at least one measuring means capable of measuring at least the contact pressure, width direction shear stress and circumferential direction shear stress of the tire is embedded, and rotation of the rotating drum. a drum drive means for controlling the speed, and the tire driving means for controlling the rotational speed before Symbol tire, and the tire angle control means for imparting a predetermined camber angle and the slip angle to the tire, the ground contact pressure of the tire, the width When the directional shear stress and the circumferential shear stress were measured simultaneously, the rotating drum and the tire were rotated together by contacting the rotating drum with a tire as a measurement object provided with the required camber angle and slip angle . It is displaced at a constant speed in the rotation axis direction of the rotary drum in the state, as well as a tire control stand is displaced in a direction approaching and separating relative to the rotating drum Apparatus for measuring the ground characteristics of the tire, characterized in that it comprises a.

  Preferably, the measuring means is a three-component force sensor capable of measuring a tire contact pressure, a width direction shear stress, and a circumferential direction shear stress. Further, the tire is relatively displaced with a constant pitch width of 1 mm or more and 4 mm or less in the rotation axis direction of the rotary drum.

  In the method for measuring the ground contact characteristics of the tire according to the present invention, the measuring means is embedded in the circumferential surface of the rotatable rotating drum, and the tire is axially rotated while rotating together with the tire in contact with the rotating drum. When moving in the direction, the assumed means embedded in the circumferential surface of the rotating drum repeatedly makes a transition with respect to the rotating shaft direction of the rotating drum with respect to the grounding region at a constant pitch width, and repeatedly repeats the grounding region Therefore, the ground contact characteristics of the tire at each pitch through which the measuring means passes can be quickly measured sequentially from the end of the ground contact region in the drum axial direction.

  For this reason, it is possible to secure a large amount of data on the grounding characteristics at different parts in the axial direction in the grounding area efficiently and in large quantities. Can be expressed clearly.

  In addition, since this measurement method does not maneuver the vehicle, the measurement can be performed indoors without using a large test site, and since only the rotating drum and the tire are moved, the air resistance is reduced. And is less susceptible to external factors such as unevenness on the test road surface, so that the ground contact characteristics of the tire can be measured with high accuracy and high reproducibility.

Furthermore, according to this measurement method, it is not necessary to take into account measurement errors due to vehicle operation, influences from external factors, etc., so that the tire condition during high speed driving and heavy load is also reproduced, and the grounding characteristics are reproduced. Therefore, the measurement limit in measuring the ground contact characteristics of the tire can be greatly improved.
Specifically, it is possible to measure up to about 400 km / h in speed and up to about 50 kN in load.

  In addition, if the camber angle and slip angle are applied to the tire as necessary, the ground contact state of the tire during cornering can be accurately reproduced. For example, the rotation speed and rotation of the tire If the rotational speed of the drum is different, it is possible to reproduce the ground contact state of the tire when the vehicle is braking / driving at various speeds.

  Furthermore, in the method for measuring the ground contact characteristics of the tire according to the present invention, at least the ground contact pressure, the width direction shear stress and the circumferential direction shear stress of the tire are simultaneously measured at the same location on the tire. Tire characteristics obtained by correlating these data without offsetting, for example, the coefficient of friction at a certain portion of the tire contact area, etc. It is possible to know the distribution of characteristics within the ground contact area.

  That is, according to the method for measuring the ground contact characteristics of the tire according to the present invention, it is possible to easily know where the axial force of the tire is generated on the road surface when the vehicle is traveling under various conditions. It is possible to quantitatively grasp the tire slip phenomenon and the distribution of the friction coefficient in the ground contact area and verify them.

  According to the tire ground contact property measuring apparatus of the present invention, in particular, a drum in which the measuring means is embedded in the peripheral surface, and a tire angle control means for giving a required camber angle and strip angle to the tire as a measurement symmetry. As a result, the method for measuring the ground contact characteristics of the tire according to the present invention can be reliably implemented, and the same effect as that obtained by the measurement method can be obtained.

  In the method and apparatus for measuring contact characteristics of a tire according to the present invention, when the measuring means is a three-component force sensor capable of measuring the contact pressure, width direction shear stress and circumferential direction shear stress of the tire, Unlike the case of separately measuring contact pressure, width direction shear stress and circumferential direction shear stress, it is possible to measure the stress state at the same point on the tire surface, and to strictly evaluate the correlation between the three. Is possible.

It is a perspective view which shows the measuring apparatus of the ground contact characteristic of the tire of this invention. It is a top view which shows a rotating drum and the tire which provided the camber angle and was made to contact | abut to this rotating drum. It is a perspective view which shows in more detail the contact area | region of a rotating drum and a tire, and the pitch width of a measurement means. It is a figure which shows the contact pressure distribution of the tire, the width direction shear stress distribution, and the circumferential direction shear stress distribution obtained by the measuring method and measuring apparatus of the contact property of the tire of this invention.

Hereinafter, the present invention will be described in detail with reference to the drawings.
In the place shown in FIG. 1, the apparatus for measuring contact characteristics of a tire according to the present invention includes at least measurement means 1 that can measure the contact pressure P, the width direction shear stress τ _x and the circumferential direction shear stress τ _y of the tire T. The rotating drum 2 embedded in the surface, the drum driving means 3 for controlling the rotation speed V _d of the rotating drum 2, the tire T as the measurement object, the direction of the rotation axis A of the rotating drum 2, and the rotating drum against (in the illustrated example, the direction perpendicular to the rotation axis a of the rotary drum 2) direction toward and away from the tire control stand 4 for displacing the, the tire driving means 5 for controlling the rotational speed V _t of the tire T And tire angle control means 6 for providing the tire T with the required camber angle CA and slip angle SA.

In the figure, the measuring means 1 is a small three-component force sensor. According to the three-component force sensor, the contact pressure P of the tire T, the width direction shear stress τ _x and the circumferential direction shear stress τ. _y can be measured.

When measuring the ground contact characteristics, the tire angle control means 6 gives a camber angle CA, a slip angle SA, or a camber angle CA to the tire T as shown in FIG. In addition to this, if the grounding force of the tire T to be brought into contact with the rotating drum 2 is adjusted, the state of the tire during cornering or the like is reproduced, and the grounding is achieved. Characteristics can be obtained.
It is also possible to measure the camber angle CA and the slip angle SA applied to the tire both at 0 °, and in this case, the ground contact characteristic when the vehicle is traveling straight is measured.

In the method for measuring the ground contact characteristics of the tire T of the present invention, for example, using the measuring device as described above, as shown in FIG. the rotary drum 2 and the tire T in a state where both are rotated, while gradually displacing the tire T in the direction of the axis of rotation a of the rotating drum 2, the ground pressure P of the tire T, the width direction shear stress tau _x and circumferential shear stress τ _y is measured.

  According to this measuring method, the measuring means 1 passes through the ground contact area 7 of the tire T every time the rotary drum 2 rotates, and the path of the measuring means 1 on the ground contact area 7 is the tire Along with the gradual displacement of T in the direction of the rotation axis A, the T is displaced with a pitch width P of each circumference.

Using the ground pressure P, width direction shear stress τ _x, and circumferential direction shear stress τ _y data obtained by the method for measuring the ground pressure of the tire T of the present invention, various ground characteristics of the tire are obtained. Can be obtained.

For example, if each of the above data is processed using a predetermined processing device, the contact pressure distribution, the width direction shear stress distribution and the circumferential direction shear stress distribution of the tire T in the contact region 7 can be expressed.
The processing apparatus is not particularly limited and includes a general-purpose numerical analysis program “MATLAB” (Mathworks).

Further, if each of the above data is correlated with each other, it is possible to calculate the friction coefficient μ of an arbitrary portion of the ground contact area 7 of the tire T, and thereby the distribution of the friction coefficient μ in the ground contact area 7. Can be obtained.
The friction coefficient μ can be calculated by the following equation (1) using the contact pressure P, the width direction shear stress τ _x and the circumferential direction shear stress τ _y .

The pitch width P can be adjusted by adjusting the rotation speed V _d of the rotary drum 2 and the displacement speed of the tire T in the direction of the rotation axis A.
That is, if slow displacement speed of the tire T with respect to the rotational speed V _d, the pitch width P is reduced, it is possible to obtain more measurement data, clearly represent the contact region of the tire at high resolution On the other hand, if the displacement speed of the tire T is increased, the measurement can be completed earlier, so that the measurement efficiency can be improved.

  In view of the balance between the measurement resolution and the measurement efficiency, the pitch width P is usually preferably about 2 mm, and more specifically in the range of 1 to 4 mm.

Further, as described above, the rotational speed V _t of the tire T and the rotational speed V _d of the rotary drum 2 can be made different. If V _t <V _d , the grounding state of the tire T during braking is set. Can be reproduced, and if V _t > V _d , the ground contact state of the tire T during driving can be reproduced. Further, when V _t = V _d , the tire T at a constant speed can be reproduced. The grounding state can be reproduced.

  In measurement, it is preferable to arrange the rotation axis A of the rotary drum 2 and the rotation axis of the tire T so that the heights are equal to each other. According to this, in particular, the camber angle CA of the tire T is set. Further, since there is an advantage that the slip angle SA can be more accurately reflected on the contact surface, a more accurate measurement can be realized.

For the measurement test, a caramel block tire T having a tire size of 205 / 55R16 was manufactured, and the tire T was mounted on the tire control stand 4 according to the position shown in FIG. The camber angle CA = 0 °, the rotational speed V _t of the tire T = 100 km / h, the rotational speed V _d of the rotary drum 2 = 100 km / h, the pitch width P = 2 mm, and the circumferential resolution = 1/3 mm. The contact pressure P, the width direction shear stress τ _x and the circumferential direction shear stress τ _y of the tire T were measured.

  Based on the data obtained by this measurement, the contact pressure distribution, the width direction shear stress distribution, and the circumferential direction shear stress distribution of the tire T were calculated, and a distribution as shown in FIG. 4 was obtained.

T Tire 1 Measuring means 2 Rotating drum 3 Drum driving means 4 Tire control stand 5 Tire driving means 6 Tire angle control means 7 Grounding area A Rotating drum rotation axis CA Camber angle SA Slip angle P Pitch width

Claims (6)

A method for measuring the ground contact characteristics of a rolling tire,
As a measurement object in which only one measuring means that can measure at least the contact pressure, width direction shear stress, and circumferential direction shear stress of a tire is embedded, and a rotating camber that can be driven to rotate is provided with the required camber angle and slip angle. While the tire is abutted and the rotating drum and the tire are both rotated, the tire is displaced at a constant speed in the rotating shaft direction of the rotating drum, and at least the tire contact pressure and the width direction shear stress are And the circumferential shear stress are simultaneously measured to obtain a contact pressure distribution, a width direction shear stress distribution and a circumferential direction shear stress distribution in the contact area of the tire with the rotating drum. Measuring method of grounding characteristics.   The method for measuring tire ground contact characteristics according to claim 1, wherein the measuring means is a three-component force sensor capable of measuring tire ground contact pressure, width direction shear stress, and circumferential direction shear stress.   The method for measuring the ground contact characteristics of a tire according to claim 1 or 2, wherein the tire is relatively displaced in a rotation axis direction of the rotating drum with a constant pitch width of 1 mm or more and 4 mm or less. A device for measuring the ground contact characteristics of a rolling tire,
At least, the ground contact pressure of the tire, and the width direction shear stress and circumferential shear stress rotating drum a is only one embedded measurable measuring means, and the drum drive means for controlling the rotational speed of the rotary drum, before Symbol Simultaneous measurement of tire driving means for controlling the rotation speed of the tire, tire angle control means for imparting the required camber angle and slip angle to the tire, and tire contact pressure, width direction shear stress and circumferential direction shear stress Sometimes, the rotating drum is brought into contact with a tire as a measuring object to which a required camber angle and slip angle are given, and the rotating drum and the tire are rotated together, and the rotating drum is rotated at a constant speed in the rotation axis direction. in displacing, and ground of the tire, characterized in that comprises a tire control stand is displaced in a direction approaching and separating relative to the rotary drum, the Sex of the measuring device.   The tire contact property measurement apparatus according to claim 4, wherein the measuring means is a three-component force sensor capable of measuring a tire contact pressure, a width direction shear stress, and a circumferential direction shear stress.   The tire ground contact characteristic measuring device according to claim 4 or 5, wherein the tire is relatively displaced in a rotation axis direction of the rotating drum with a constant pitch width of 1 mm or more and 4 mm or less.