JP2016218017A - Antiwear performance evaluation method of rubber material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To evaluate an antiwear performance in turning traveling of a rubber material with a high precision.SOLUTION: A method evaluates an antiwar performance of a rubber material worn by making a cylindrical rubber material G travel in turning on a pseudo road surface 12B. The rubber material G is given with a plurality of types of turning conditions determined by a slip angle θ and a grounding load so as to travel in turning on the pseudo road surface 12B. The method includes at least: a first step of measuring a lateral force acting on the rubber material G; a second step of calculating a regression expression between the turning conditions and the lateral force; a third step of determining evaluation turning conditions corresponding to the predetermined evaluated lateral force on the basis of the regression expression; and a fourth step of calculating wear energy of the rubber material G by the evaluation turning conditions.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for evaluating the wear resistance of a rubber material, which can accurately evaluate the wear resistance of a rubber material during turning.

  Conventionally, the evaluation of the wear resistance performance during turning of a rubber material has been performed using, for example, an indoor wear tester having a rotating simulated road surface. Specifically, a cylindrical rubber material is given a predetermined slip angle and contact load with respect to the simulated road surface, and is evaluated based on the amount of wear of the rubber material when rotating at a predetermined speed. It was. That is, in the conventional method for evaluating wear resistance during turning, the evaluation is based on the wear amount of the rubber material corresponding to the slip angle to be evaluated.

  However, a rubber material having a low rubber hardness has a small lateral force during turning as compared with a rubber material having a high rubber hardness, and thus needs to turn at a large slip angle. From this, the inventors speculated that when the turning radii are the same, the rubber materials having different rubber hardness (rubber compounding) have different slip angles but the same lateral force. Therefore, in the evaluation method based on the amount of wear corresponding to the slip angle as described above, the lateral force acting on the rubber material, that is, the turning radius is not evaluated under the same condition, and the wear resistance during turning is the same. There was a problem that performance could not be evaluated with high accuracy.

JP 2013-36900 A

  The present invention has been devised in view of the above problems, and has as its main object to provide an evaluation method capable of evaluating the wear resistance performance of a rubber material during turning with high accuracy.

  The present invention is a method for evaluating the wear resistance performance of a rubber material by causing a cylindrical rubber material to wear by rotating on a simulated road surface. The rubber material has a slip angle and a ground load. A first step of giving a plurality of types of turning conditions to be determined and turning on the pseudo road surface, and measuring at least a lateral force acting on the rubber material, a regression equation of the turning conditions and the lateral force A second step of calculating the calculation, a third step of acquiring an evaluation turning condition corresponding to a predetermined evaluation lateral force based on the regression equation, and calculating wear energy of the rubber material under the evaluation turning condition And a fourth step.

  In the wear resistance performance evaluation method for a rubber material according to the present invention, it is desirable that the turning condition is represented by a product of the ground contact load and the slip angle.

  In the wear resistance performance evaluation method for a rubber material according to the present invention, it is desirable that the turning condition is represented by a ratio between the ground contact load and the slip angle.

  In the method for evaluating wear resistance performance of a rubber material according to the present invention, the first step further includes a step of measuring a contact length between the rubber material and the simulated road surface, and the fourth step includes the contact length. And calculating the amount of slip of the rubber material with respect to the simulated road surface during the turning of the rubber material in the first step using the slip amount and the slip force, and the wear energy using the slip amount and the lateral force. Preferably including a calculating step.

  The method for evaluating the wear resistance performance of a rubber material according to the present invention includes a fifth step of turning the rubber material on the pseudo road surface based on the evaluation turning condition and measuring at least the amount of wear of the rubber material; Preferably, the method includes a sixth step of calculating a relationship between the wear amount and the wear energy.

  In the wear resistance performance evaluation method for a rubber material according to the present invention, the rubber material includes a first rubber material and a second rubber material having a different composition from the first rubber material, and the second step includes the step of Calculating a first regression equation indicating a relationship between the turning condition of the first rubber material and the lateral force, and a second regression equation indicating a relationship between the turning condition of the second rubber material and the lateral force; The third step includes obtaining a first evaluation turning condition corresponding to a predetermined evaluation lateral force based on the first regression equation, and calculating the evaluation lateral force based on the second regression equation. Obtaining a corresponding second evaluation turning condition, wherein the fourth step calculates a first wear energy of the first rubber material under the first evaluation turning condition, and the second evaluation turning. Calculating a second wear energy of the second rubber material under conditions. To, said first wear energy, it is desirable to include a step of comparing the second wear energy.

  The method for evaluating the wear resistance of a rubber material according to the present invention wears a cylindrical rubber material by rotating it on a simulated road surface. Then, the rubber material is given a plurality of types of turning conditions determined by the slip angle and the contact load, and is made to turn on the pseudo road surface, and at least the lateral force acting on the rubber material is measured, and the turning A second step of calculating a regression equation of the condition and the lateral force; a third step of acquiring an evaluation turning condition corresponding to a predetermined evaluation lateral force based on the regression equation; and a rubber under the evaluation turning condition And a fourth step of calculating the wear energy of the material. Thus, in the present invention, the wear resistance performance can be evaluated based on the wear energy of the rubber material corresponding to a certain evaluation lateral force without being based on the slip angle. Therefore, in the method for evaluating the wear resistance of a rubber material according to the present invention, the wear resistance of the rubber material during turning can be evaluated with high accuracy. In particular, when there are a plurality of types of rubber materials different from the blending, the wear resistance performance between different rubber materials can be evaluated with higher accuracy by evaluating the wear energy under the same evaluation turning condition.

It is a perspective view of the friction testing machine for enforcing the abrasion resistance performance evaluation method of the rubber material of the present invention. (A) is a perspective view of the rubber material of this embodiment, (b) is a perspective view of the rubber material of other embodiment. It is a top view of a rubber material and a pseudo road surface. It is a graph which shows the regression equation of the turning conditions and lateral force which were calculated with the evaluation method of this invention. It is a graph which shows the regression equation of the wear energy and the wear amount which were calculated with the evaluation method of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The method for evaluating the wear resistance performance of the rubber material of the present embodiment (hereinafter, sometimes simply referred to as “evaluation method”) is for evaluating the wear resistance performance of the rubber material during cornering indoors, As shown in FIG. 1, an indoor wear tester 1 (hereinafter sometimes simply referred to as “tester 1”) can be used.

  The testing machine 1 evaluates the wear resistance of the rubber material G from the wear state of the test piece 10 made of the rubber material G, for example. For example, various types of testing machines 1 can be used as long as they can perform a vulcanized rubber abrasion test standardized in JIS K6263. In the present embodiment, a rubber wear tester (model: LAT100) manufactured by Hiraizumi Yoko Co., Ltd. is used.

  The test machine 1 of the present embodiment includes a turntable 12 that rotates the test piece 10, a test piece support portion 13 that supports the rubber material G, and a base 14 that supports the turntable 12 and the test piece support portion 13. It is out. The turntable 12, the test piece support 13 and the base 14 are accommodated in a housing (not shown) provided with a switch for operating and stopping the test machine 1, for example.

  As shown in FIG. 2 (a), the test piece 10 of the present embodiment is formed of a cylindrical rubber material G, and a hole 10o that is rotatably supported by the test piece support portion 13 is formed at the center thereof. Is provided. For example, the test piece 10 has an outer diameter D1 of about 40 to 80 mm and a width W1 of about 4 to 20 mm from the viewpoint of evenly wearing the outer peripheral surface 10a and measuring the lateral force with high accuracy.

  FIG. 2B shows another embodiment of the test piece 10. As shown in FIG. 2B, the rubber material G of the test piece 10 is, for example, cut out from a region including the contact surface of the tread portion of the tire manufactured by a known manufacturing method, for example, a thickness t1 May include a sheet-like rubber material Ga having a thickness of about 0.5 to 4 mm. The rubber material Ga is made of, for example, resin and is wound around the outer surface of the cylindrical body 10b having the hole 10o. Such a test piece 10 can reproduce the wear state of the tire with high accuracy.

  As shown in FIG. 1, the turntable 12 includes a disc-shaped turntable 12A and a pseudo road surface 12B fixed to the turntable 12A. The rotary table 12A is fixed to the upper end side of the vertical shaft 19 that protrudes upward from the base 14. Further, the lower end side of the vertical shaft 19 is fixed to an electric motor (not shown) incorporated in the base 14. Such a rotating disk 12 can be rotated around a vertical axis by driving an electric motor. The turntable 12 preferably has, for example, an inverter that controls the rotational speed of the simulated road surface 12B.

  The simulated road surface 12B is formed of, for example, a plurality of abrasive grains (not shown). The particle size of the simulated road surface 12B is preferably about 24 to 240 (mesh) in order to appropriately wear the rubber material G so as to approximate the wear state of the tire worn on the asphalt road surface.

  The test piece support portion 13 includes a support portion 15 that supports the test piece 10 so as to be rotatable about a horizontal axis, and a cylinder mechanism 16 that moves the test piece 10.

  One end of the support 15 is horizontally inserted into the hole 10o (shown in FIG. 2) of the test piece 10 via a bearing 29 such as a bearing, and the other end of the horizontal shaft 15a is placed horizontally. And a horizontal shaft fixing portion 15b pivotally supported around the shaft. It is desirable that the horizontal shaft 15a is provided with a measuring means (not shown) having a well-known structure made of, for example, a load cell capable of measuring a lateral force, a ground load, a longitudinal force, and the like acting on the rubber material G.

  The cylinder mechanism 16 includes a rod 16a that expands and contracts in the longitudinal direction, a cylinder 16b that supports the rod 16a so that it can be inserted and removed, and an electric motor (not shown) that expands and contracts the rod 16a. One end of a plate-like connecting member 17 is fixed to the tip of the rod 16a, and a horizontal shaft fixing portion 15b is fixed to the other end of the connecting member 17. Thereby, the cylinder mechanism 16 can move the test piece 10 perpendicularly with respect to the simulated road surface 12B by expansion and contraction of the rod 16a.

  Further, the cylinder 16b of the present embodiment is supported on the base 14 so as to be rotatable about a vertical axis. Thereby, the test piece support part 13 can set slip angle (theta) etc. with respect to the simulated road surface 12B to the test piece 10. FIG.

  Next, a method for evaluating the wear resistance performance of a rubber material using such a testing machine 1 will be described below with specific examples. In the evaluation method of the present embodiment, first, a first rubber material G1 and a second rubber material G2 having a different composition from the first rubber material G1 are prepared. In the present embodiment, the following steps are similarly performed on the first rubber material G1 and the second rubber material G2.

  Next, a first step of measuring the lateral force acting on the rubber material G and the contact length L (not shown) between the rubber material G and the simulated road surface 12B is performed. Specifically, in the first step, for example, the rubber material G is attached to the horizontal shaft 15a, the rod 16a of the cylinder mechanism 16 is contracted downward, and the rubber material G is subjected to a predetermined turning condition on the simulated road surface 12B. Ground based. As the turning condition, the contact load of the rubber material G to the simulated road surface 12B and the slip angle θ of the rubber material G with respect to the simulated road surface 12B are used. The slip angle θ is a deviation angle between the traveling direction A1 of the rubber material G and the rotation direction of the rubber material G (that is, the direction of the equatorial plane 10c of the rubber material G). The traveling direction A1 of the rubber material G is a direction orthogonal to the straight line 18 connecting the center 12c of the rotating disk 12 and the grounding center 10s of the rubber material G (that is, a tangential direction of the disk-shaped rotating disk 12). is there. The contact length L is the circumferential length of the cylindrical rubber material G.

  For example, the slip angle θ is preferably 1 to 90 degrees, more preferably 2 to 45 degrees, and more preferably 3 to 30 degrees in order to accurately reproduce the actual vehicle running of the tire. From the same viewpoint, the ground load is preferably about 10 to 120 N, for example. Further, the peripheral speed at the ground contact center 10s of the rubber material G on the simulated road surface 12B is preferably 1 to 40 km / h.

  Next, for example, the pseudo road surface 12B is driven and rotated, and the rubber material G is freely rolled. Thereby, the rubber material G is worn by friction with the simulated road surface 12B. And the lateral force which acts on the rubber material G at this time is measured by the above-mentioned measuring means. Further, it is desirable that the ground contact length L is measured before the simulated road surface 12B is driven to rotate or after the rotation is stopped after being grounded under a turning condition. Furthermore, it is desirable that the contact width W (not shown) between the rubber material G and the simulated road surface 12B is measured simultaneously with the measurement of the contact length L. As the ground contact width W, the length in the axial direction of the approximately cylindrical rubber material G may be employed.

  In the first step of this embodiment, the rubber material G is caused to turn under a plurality of types of turning conditions having different slip angles θ or contact loads, and measurement parameters such as lateral force under each turning condition are measured. The travel distance of rubber material G (drive time of turntable 12), the number of measurement parameters, the measurement time, and the like are variously selected. Further, as the peripheral speed of the ground contact center 10s of the rubber material G, a value determined in advance from 1 to 40 km / h is adopted.

  Next, a second step of calculating a regression equation Ka between the turning condition adopted in the first step and the lateral force measured under the turning condition is performed. In the second step of the present embodiment, the first regression equation K1 indicating the relationship between the turning condition of the first rubber material G1 and the lateral force, and the second representing the relationship between the turning condition of the second rubber material G2 and the lateral force. The regression equation K2 is calculated. Various regression equations can be selected, but it is desirable to adopt a power regression equation in order to evaluate wear resistance performance with higher accuracy.

FIG. 4 is a graph showing an example of the first regression equation K1 and the second regression equation K2 calculated in the second step. The horizontal axis in FIG. 4 is the product (N · degree) of the ground load and the slip angle θ, which is the turning condition, and the vertical axis is the measured lateral force (N). On the horizontal axis, the larger the value, the more intense the turn. As shown in FIG. 4, in this example, the five types of turning conditions in which the contact load and the slip angle θ were as follows were given. In addition, although the turning conditions are not limited to the following example, it is desirable to provide at least three kinds, and it is more desirable that the kind is large. Further, as the horizontal axis, a turning condition that is a ratio (N / degree) between the contact load and the slip angle θ can be adopted.
Swivel condition 1 ... Contact load: 40N, slip angle θ: 6 degrees Swivel condition 2 ... Ground load: 40N, slip angle θ: 9 degrees Swivel condition 3 ... Ground load: 75N, slip angle θ: 12 Degree Turning condition 4 ... Contact load: 100N, slip angle θ: 9 degrees Turn condition 5 ... Ground load: 100N, slip angle θ: 12 degrees

  Next, a third step of acquiring an evaluation turning condition corresponding to a predetermined evaluation lateral force A is performed based on the regression equation Ka. The third step of the present embodiment includes a step of acquiring the first evaluation turning condition and a step of acquiring the second evaluation turning condition. The first evaluation turning condition is a parameter acquired from the first rubber material G1 corresponding to the evaluation lateral force A based on the first regression equation K1. The second evaluation turning condition is a parameter acquired from the second rubber material G2 corresponding to the evaluation lateral force A based on the second regression equation K2. The evaluation turning condition of the present embodiment is indicated by the product (N · degree) of the contact load and the slip angle θ. In the case of the present embodiment, as shown in FIG. 4, for example, when 38N is selected as the evaluation lateral force A, 336.71 is acquired as the first evaluation turning condition, and as the second evaluation turning condition. 360.95 is obtained.

  Next, a fourth step of calculating the wear energy of the rubber material G under the evaluation turning condition is performed. In the fourth step of this embodiment, the step of calculating the first wear energy of the first rubber material G1 under the first evaluation turning condition and the second wear energy of the second rubber material G2 under the second evaluation turning condition are calculated. And a calculating step.

The wear energy is calculated by the amount of slip and the lateral force with respect to the simulated road surface 12B when the rubber material G is turning in the first step. In the present embodiment, the wear energy is calculated by the following formula (1) that is the product of the slip amount and the shear stress. Shear stress is a lateral force per contact area. The slip amount is calculated by the following equation (2) which is the product of the contact length L (mm) and the slip angle θ (degrees). At this time, the slip angle θ (degrees) may be calculated using a load (usually 40 N in the case of a passenger car) that is a contact pressure equivalent to the actual vehicle based on the evaluation turning condition. In addition, a value corresponding to the slip angle θ (degrees) may be employed as the ground contact area (L × W).
Wear energy (N / mm) = L x tanθ x F1 / (L x W)
= Tanθ x F1 / W (1)
Slip amount (mm) = L x tanθ (2)
The above symbols are as follows.
F1: Evaluation lateral force A (N)
W: Grounding width (mm)
L x W: Grounding area (mm ² )

  In the case of the example in FIG. 4, the first wear energy is calculated as 304 when the first evaluation turning condition is 336.71 from the above formulas (1) and (2). When the second evaluation turning condition is 360.95, the second wear energy is calculated as 326. Thus, in this embodiment, since wear energy is calculated using an evaluation turning load, it is estimated that the wear energy at the time of cornering with the same turning radius can be expressed with high accuracy. Note that the first wear energy and the second wear energy may be obtained by a finite element method (FEM) using parameters of slip angle θ, ground load, complex elastic modulus of rubber material G, and loss tangent.

  Next, based on the evaluation turning condition, the fifth step of turning the rubber material G on the pseudo road surface and measuring the wear amount of the rubber material G is performed. The turning of the rubber material G in the fifth step is performed in the same manner as the turning of the rubber material G in the first step.

  In the fifth step of the present embodiment, the wear amount is measured based on the evaluation turning condition acquired in the third step. In the present embodiment, the fifth step measures the wear amount of the first rubber material G1 based on the first evaluation turning condition, and measures the wear amount of the second rubber material G2 based on the second evaluation turning condition. And a process of performing. In the fifth step, for example, the wear energy corresponding to the measured wear amount is calculated based on the equations (1) and (2). That is, the wear energy and the wear amount calculated in the fifth step correspond to the evaluation turning condition. The amount of wear and the wear energy are not limited to those measured in such a process. For example, in the first process, the wear amount and the wear energy may be measured together with the lateral force based on the turning condition.

  Next, a sixth step of calculating the relationship between the wear amount and the wear energy is performed. In the sixth step of the present embodiment, a regression equation Kb between the wear amount and the wear energy of the rubber material G measured in the fifth step is calculated.

  The regression equation Kb calculated in the sixth step of the present embodiment is the third regression equation K3 of the wear amount and the first wear energy in the first rubber material G1, and the wear amount and the second wear in the second rubber material G2. 4th regression equation K4 with energy is included.

  FIG. 5 is a graph showing an example of the third regression equation K3 and the fourth regression equation K4. The horizontal axis in FIG. 5 is the wear energy (N / mm), and the vertical axis is the wear amount (mm). As shown in FIG. 5, in this example, the regression equation Kb is calculated in the fifth step by giving evaluation turning conditions corresponding to five types of lateral forces. The evaluation turning conditions are not limited to five types, and may be, for example, three or more types.

  Next, a seventh step of evaluating the wear resistance performance of the rubber material is performed by comparing the first wear energy of the first rubber material G1 and the second wear energy of the second rubber material G2. In the seventh step of the present embodiment, the wear amount of the first rubber material G1 based on the first wear energy is compared with the wear amount of the second rubber material G2 based on the second wear energy. The amount of wear of the first rubber material G1 is determined from the wear energy calculated in the fourth step and the third regression equation K3 calculated in the sixth step. The amount of wear of the second rubber material G2 is obtained from the second wear energy calculated in the fourth step and the fourth regression equation K4 calculated in the sixth step.

  Specifically, in the example of FIG. 5, when the first wear energy calculated in the fourth step is 304, the wear amount is calculated to be 6.53 mm from the third regression equation K3. From the fourth regression equation K4, when the second wear energy calculated in the fourth step is 326, the wear amount is calculated to be 7.53 mm. Therefore, in this example, it can be determined that the first rubber material G1 has a smaller wear amount and better wear resistance than the second rubber material G2.

  Thus, in the evaluation method of the rubber material G of the present embodiment, the rubber material G is given a plurality of types of turning conditions determined by the slip angle θ and the contact load, and the lateral force acting on the rubber material G is given. measure. Accordingly, the wear resistance performance can be evaluated under the condition that the lateral force acting on the rubber material G, that is, the turning radius is the same. Therefore, in the evaluation method of the present embodiment, the wear resistance performance of the rubber material G during cornering can be evaluated with high accuracy.

  In the present embodiment, the wear resistance performance of the rubber material at the time of turning travel was evaluated using two types of rubber materials G having different blends, but the present invention is not limited to such an aspect, and for example, 3 or more It is also possible to evaluate using a plurality of types of rubber materials G.

In this embodiment, in the first step and the fifth step, the rubber material G is freely rolled with respect to the simulated road surface 12B. For example, the rubber material G and the simulated road surface 12B are driven and rotated. Also good. In this case, the slip amount and wear energy calculated in the fourth step and the sixth step are calculated by the following equations (3) and (4), respectively. Even when each of the rubber material G and the pseudo road surface 12B is driven and rotated, except for the calculation formulas of the slip amount and the wear energy, the same steps as in the case of free rolling of the rubber material G are performed, and thus the description thereof is omitted. .
Slip amount (mm) = L × tan θ + L (V1− (V2 × cos θ)) / V1 (3)
Wear energy (N / mm)
= L × tan θ × F1 / (L × W) + {L × (V1− (V2 × cos θ)) / V1 × F2} / (L × W)
= Tan θ × F1 / W + {(V1− (V2 × cos θ)) / V1} × F2 / W (4)
The above symbols are as follows.
F2: Longitudinal force (N) which is a reaction force in the traveling direction acting on the rubber material G
V1: Peripheral speed of rubber material G (km / h)
V2: peripheral speed (km / h) at the center of contact of the rubber material G on the simulated road surface 12B

  As mentioned above, although embodiment of this invention was explained in full detail, this invention can be changed and implemented in various aspects, without being limited to the said embodiment.

G Rubber material 12B Simulated road surface

Claims (6)

A method for evaluating wear resistance performance of the rubber material by causing a cylindrical rubber material to wear by rotating on a simulated road surface,
A first step of measuring the lateral force acting on the rubber material by giving the rubber material a plurality of types of turning conditions determined by a slip angle and a ground load and turning on the pseudo road surface;
A second step of calculating a regression equation of the turning condition and the lateral force;
A third step of acquiring an evaluation turning condition corresponding to a predetermined evaluation lateral force based on the regression equation;
And a fourth step of calculating the wear energy of the rubber material under the evaluation turning condition.   The method for evaluating wear resistance of a rubber material according to claim 1, wherein the turning condition is represented by a product of the ground load and the slip angle.   The method for evaluating wear resistance of a rubber material according to claim 1, wherein the turning condition is represented by a ratio between the ground load and the slip angle. The first step further includes a step of measuring a contact length between the rubber material and the simulated road surface,
The fourth step uses the contact length and the slip angle to calculate a slip amount with respect to the simulated road surface when the rubber material turns in the first step;
The method for evaluating the wear resistance of a rubber material according to any one of claims 1 to 3, further comprising a step of calculating the wear energy by using the slip amount and the lateral force. A fifth step of turning the rubber material on the pseudo road surface based on the evaluation turning condition and measuring at least the amount of wear of the rubber material;
The method for evaluating the wear resistance of a rubber material according to any one of claims 1 to 4, further comprising a sixth step of calculating a relationship between the wear amount and the wear energy. The rubber material includes a first rubber material and a second rubber material having a different composition from the first rubber material,
In the second step, a first regression equation showing a relationship between the turning condition of the first rubber material and the lateral force, and a second regression showing a relation between the turning condition of the second rubber material and the lateral force. Calculate the regression equation,
The third step includes obtaining a first evaluation turning condition corresponding to a predetermined evaluation lateral force based on the first regression equation, and calculating the evaluation lateral force based on the second regression equation. Obtaining a corresponding second evaluation turning condition,
The fourth step calculates a first wear energy of the first rubber material under the first evaluation turning condition, and calculates a second wear energy of the second rubber material under the second evaluation turning condition. Including the steps of:
The method for evaluating wear resistance of a rubber material according to any one of claims 1 to 5, further comprising a step of comparing the first wear energy and the second wear energy.

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