JP2019113406A - Evaluation method of uneven wear resistance of rubber member and tire manufacturing method using the same - Google Patents

Abstract

To evaluate uneven wear resistance of a rubber member.SOLUTION: A method for evaluating uneven wear resistance of a rubber member includes: a step K1 of preparing a plurality of types of rubber samples G which have the same combination and different rigidity; a step K2 of conducting a wear test on the rubber samples under the same test conditions by using a wear tester; a step K3 of measuring the amount of wear of the rubber samples; and a step K4 of determining the quality of the uneven wear resistance of the rubber member on the basis of a parameter related to difference in the amount of wear.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for evaluating the uneven wear resistance of a rubber member and a tire manufacturing method using the same.

  Heretofore, various methods for evaluating the wear performance of a rubber member have been proposed. For example, in Patent Document 1 below, a process of cutting a rubber sample from a tread portion of a tire, a process of abrading the rubber sample with an indoor abrasion tester, and evaluation of wear resistance performance based on a wear state of the rubber sample And a method comprising the steps is described.

Patent No. 5542104 gazette

  For example, even if the rubber composition of the tread portion of the tire and the like is the same, even if the rubber composition is different depending on the shape, size, etc., the rigidity may show different wear characteristics. For example, with respect to two types of rubber members having the same rubber composition, those having high rigidity may exhibit good wear characteristics, but may show characteristics of early wear when the rigidity is low. Such characteristics appear as uneven wear, for example, in a tire tread, various rollers and the like in which blocks of various rigidity are formed. Therefore, the above-mentioned evaluation method could not evaluate such uneven wear performance.

  The present invention has been made in view of the above problems, and its main object is to provide a method for evaluating the uneven wear resistance of a rubber member.

  The first invention of the present application is a method for evaluating the uneven wear resistance performance of a rubber member, and a step of preparing a plurality of rubber samples including at least a first rubber sample and a second rubber sample having the same composition and different rigidity. A step of performing an abrasion test on the first rubber sample and the second rubber sample under the same test conditions using an abrasion tester, and after the abrasion test, the first rubber sample and the second rubber sample Of the uneven wear resistance of the rubber member based on a parameter related to the difference between the amount of wear of the first rubber sample and the amount of wear of the second rubber sample; And the step of

  In the method for evaluating the uneven wear resistance of a rubber member according to the present invention, it is desirable that the rubber sample be collected from a tire.

  In the method for evaluating the uneven wear resistance of a rubber member according to the present invention, it is desirable that the rubber sample be collected from a tread portion of a tire.

  In the method for evaluating the uneven wear resistance of a rubber member according to the present invention, it is desirable that the first rubber sample and the second rubber sample be in the form of a sheet having the same length and different widths.

  In the method for evaluating the uneven wear resistance of a rubber member according to the present invention, it is desirable that the wear tester be an indoor wear tester.

  In the method of evaluating uneven wear resistance of a rubber member according to the present invention, it is preferable that the parameter includes a ratio between the amount of wear of the first rubber sample and the amount of wear of the second rubber sample.

  In the method of evaluating the uneven wear resistance of a rubber member according to the present invention, it is desirable that the step of determining determines that the uneven wear resistance is good as the ratio is closer to 1.

  In the method for evaluating the uneven wear resistance of a rubber member according to the present invention, it is desirable that the determining step determines that the uneven wear resistance is good when the ratio is in the range of 1 ± 0.2.

  A second invention of the present application is a tire manufacturing method, and includes a step of manufacturing a tire component with the same composition as the rubber member determined to be good by the evaluation method of the first invention.

  In the tire manufacturing method according to the present invention, it is desirable that the component is disposed in the tread portion.

  In the evaluation method of the uneven wear resistance performance of the rubber member of the present invention, it relates to the difference between the amount of wear of the first rubber sample and the amount of wear of the second rubber sample having the same composition and different rigidity as the first rubber sample. The process of determining the quality of the uneven wear resistance performance of a rubber member based on a parameter is included. As described above, according to the evaluation method of the present invention, even if the composition is the same, it is possible to evaluate the characteristic that the wear characteristics change largely due to the change of the rigidity, that is, the uneven wear resistance performance.

It is a flowchart which shows the process sequence of the evaluation method of this invention. It is the schematic explaining the process to prepare. It is a perspective view which shows an example of the abrasion tester used by this invention. It is the elements on larger scale of the abrasion tester of FIG. It is an expansion perspective view explaining a roller body.

Hereinafter, an embodiment of the present invention will be described based on the drawings.
The method for evaluating the uneven wear resistance of the rubber member of the present embodiment (hereinafter sometimes referred to simply as the “evaluation method”) includes, for example, various rollers for conveyance, a belt, etc. It is possible to evaluate the uneven wear resistance of any rubber member. The evaluation method of the present embodiment is particularly suitable for evaluating the uneven wear resistance performance of the tread rubber Tg of the tread portion Ta of the tire T (shown in FIG. 2). Hereinafter, in the present specification, an evaluation method in the case where the tread rubber Tg is used as the rubber member Ga will be described.

  FIG. 1 is a flowchart showing the processing procedure of the evaluation method of the present embodiment. As shown in FIG. 1, in the present embodiment, the evaluation method includes a step K1 of preparing a rubber sample G (shown in FIG. 2), a step K2 of performing an abrasion test of the rubber sample G, and an abrasion of the rubber sample G. It includes a step K3 of measuring the amount and a step K4 of judging the quality of the uneven wear resistance performance.

  FIG. 2 is a schematic view illustrating the preparing step K1. As shown in FIG. 2, a plurality of types of rubber samples G are prepared, including, for example, at least a first rubber sample G1 and a second rubber sample G2 having different stiffnesses. As shown in FIG. 2, in the present embodiment, two types of rubber samples G are prepared. However, in the evaluation method of the present embodiment, many types of rubber samples G having different rigidity may be prepared.

  In the preparation step K1 of the present embodiment, the rubber sample G is taken from the tire T. The rubber sample G is a tread rubber Tg collected from the tread portion Ta including the tread surface T1 of the tire T in the present embodiment. Since the tread rubber Tg of this embodiment is formed by the same composition, the first rubber sample G1 and the second rubber sample G2 have the same rubber composition.

  The tire T includes, for example, a pneumatic tire for a passenger car, a heavy load vehicle, a motorcycle, and the like, and a non-pneumatic tire not filled with air, and various types of tires are suitably employed.

  Grooved bodies (not shown) such as a plurality of main grooves and lateral grooves are formed on the tread surface T1 of the tread portion Ta, and a plurality of land portions are provided between the main grooves and between the main grooves and the tread end. It is formed. Each land portion is, for example, formed to have different rigidity. The tread portion Ta may be, for example, an aspect in which only a plurality of main grooves are formed, or an aspect in which a groove-like body is not formed.

  The rubber sample G is cut out of the tread portion Ta using, for example, machining or a cutting tool such as a knife. Preparation of rubber sample G is not limited to such an aspect.

  In the present embodiment, the first rubber sample G1 and the second rubber sample G2 have different stiffnesses by making their widths W different. In the present embodiment, the width Wa (shown in FIG. 5) of the first rubber sample G1 is formed smaller than the width Wb of the second rubber sample G2. However, of course, the width Wa of the first rubber sample G1 may be formed larger than the width Wb of the second rubber sample G2. In addition, as an aspect which makes rigidity different, it is not limited to the aspect of this embodiment, For example, you may differ thickness t1 of rubber sample G, Moreover, the different groove-like body to rubber sample G is used. It may be formed. In addition, when plural types of rubber samples G are prepared, it is desirable that the rigidity, that is, the width W be different for each rubber sample G. As used herein, "rigid" refers to the ability to withstand wear due to frictional forces and the like.

  Next, step K2 of performing a wear test is performed. A well-known abrasion tester M is used in step K2 in which the abrasion test of the present embodiment is performed. As the wear tester M, for example, various machines can be adopted as long as they can perform a wear test of a vulcanized rubber standardized to JIS K6263. The wear tester M is preferably an indoor wear tester that can be used indoors. Thereby, for example, by making the temperature and humidity in the room constant, it is possible to evaluate the uneven wear resistance performance with high accuracy. In the present embodiment, one according to a rubber wear tester (model: LAT 100) manufactured by Hiraizumi Yoko Ltd. is employed.

  As shown in FIGS. 3 and 4, the wear tester M is formed, for example, in the shape of a rectangular parallelepiped, and on the front panel p, for example, switches sw for stopping the wear tester M, test conditions, A display unit m to be displayed is provided.

  The abrasion tester M of the present embodiment includes a grinding wheel surface 4 rotating in a vertical plane about an axis ch1 orthogonal to the vertical plane, and a roller body 5 rotatably supported by an axis 7 parallel to the vertical plane. It is comprised including. These various members are disposed on the front of the vertical base B. The plane on which the grindstone surface 4 rotates is a vertical plane, but it goes without saying that it may be a horizontal plane.

  The grindstone surface 4 is formed, for example, in an annular shape having a certain width on a disc-shaped rotary table 8 fixed to the shaft ch1.

  For example, a motor (not shown) disposed on the back side of the base B is connected to the axis ch1. By the drive of the motor, the rotary table 8 and the grindstone surface 4 rotate around the axis ch1.

  It was tested using a wear test machine M of this embodiment and a test result when a tire T was tested for its partial wear resistance performance by running an actual car outdoors (hereinafter sometimes referred to simply as "real car running") It is desirable to ensure high correlation with the test results from time to time. For this purpose, the particle size of the grinding wheel surface 4 is preferably, for example, about 40 to 240 mesh.

  As shown in FIG. 5, the roller body 5 has a cylindrical shape having a through hole 5b at its center. One end 7i side of the shaft 7 (shown in FIG. 4) is fixed to the through hole 5b via, for example, a bearing. Thus, the roller body 5 can rotate around the shaft 7.

  For example, the rubber sample G is fixed to the outer peripheral surface 5 a of the roller body 5. In the present embodiment, the rubber sample G is continuously worn by pressing the roller body 5 in contact with the rotating grindstone surface 4.

  As described above, in order to ensure a high correlation between the two test results, it is desirable that the load F caused by the pressure applied to the grinding surface 4 of the roller body 5 including the rubber sample G be, for example, 20 to 100N.

  The roller body 5 is desirably formed of a rubber material, for example, in order to ensure strong adhesion with the rubber sample G. The size of the roller body 5 is not particularly limited, and for example, the outer diameter d1 is 70 to 80 mm, and the width W1 is 15 to 22 mm.

  The shape of the rubber sample G is preferably, for example, a sheet shape such as a rectangular shape. The rubber sample G preferably has a thickness t1 of 0.5 to 4.0 mm, for example. If the thickness t1 decreases, the abradable amount of the rubber sample G decreases, which may make it impossible to perform the abrasion test with high accuracy. Conversely, when the thickness t1 is increased, bending of the rubber sample G becomes difficult, and there is a possibility that the rubber sample G can not be wound around the outer peripheral surface 5a of the roller body 5.

  The width W of the rubber sample G is desirably, for example, 4 mm or more in order to measure the amount of wear with high accuracy. When the width W of the rubber sample G is larger than the width W1 of the roller body 5, stress concentration acts on the rubber sample G, and there is a possibility that the rubber sample G can not be worn accurately. For this reason, it is desirable that the upper limit value of the width W of the rubber sample G be the same as the width W1 of the roller body 5. It is desirable that the length of each rubber sample G be the same.

  As shown in FIG. 3, the abrasion tester M of the present embodiment is provided with a roller body moving tool 9 for moving the roller body 5. The roller body moving tool 9 has, for example, a cylinder mechanism 10 having a known structure for moving the roller body 5 vertically with respect to the grinding surface 4 and a rotating mechanism 11 having a known structure for moving the roller body 5 parallel to the grinding surface 4; And a reinforcing member 13 of a known structure for facilitating the movement of the roller body 5.

  The rotation mechanism 11 is preferably, for example, capable of making the tangential direction of the circumference of the roller body 5 different from the tangential direction of the circumference of the grindstone surface 4 and giving the slip angle α to the roller body 5. When the slip angle α is given to the roller body 5, the frictional force between the grindstone surface 4 and the rubber sample G becomes large, and the rubber sample G can be efficiently worn in a short time.

  The slip angle α is not particularly limited. For example, the slip angle α is 3 to 15 degrees in order to ensure a high correlation between the test result of the uneven wear resistance performance during actual running and the test result according to the present embodiment. Is desirable.

  The wear tester M may include a temperature control device (not shown) of a known structure that changes the temperature of the grinding surface 4. This further enhances the evaluation accuracy of the rubber member Ga.

  Further, the wear tester M may be provided with an injector (not shown) of a known structure for injecting a sand-like material between the rubber sample G and the grindstone surface 4. Such an injection device serves to suppress re-adhesion of scraps discharged due to the wear between the grinding surface 4 and the rubber sample G from adhering to the rubber sample G. Thereby, since the mass after abrasion of rubber sample G can be measured with sufficient accuracy, for example, the amount of abrasion (mass) can be measured correctly by the mass difference before and behind abrasion.

  In the step K2 of performing the abrasion test, the first rubber sample G1 and the second rubber sample G2 are abrasion-tested under the same test conditions using an abrasion tester M. The same test conditions include, for example, the same conditions including the slip angle α, the load F of the pressure applied to the wheel surface 4 of the roller body 5, the rotational speed of the wheel surface 4, and the temperature and humidity of the room. The same test conditions in this embodiment do not include making the width Wa of the first rubber sample G1 and the width Wb of the second rubber sample G2 the same. The same applies to the case where a wear test is performed using a plurality of rubber samples G.

  Next, step K3 of measuring the amount of wear is performed. In step K3 of measuring the amount of wear of the present embodiment, the amount of wear f1 of the first rubber sample G1 and the amount of wear f2 of the second rubber sample G2 are measured. Each amount of wear can be accurately measured by, for example, a well-known mass spectrometer, such as a balance.

  Next, determination step K4 is performed. In the step K4 of the present embodiment, the uneven wear resistance of the rubber member Ga is determined based on the parameter P related to the difference between the wear amount f1 of the first rubber sample G1 and the wear amount f2 of the second rubber sample G2. Good or bad is judged. As described above, in the evaluation method of the present embodiment, even if the same combination is included by including the respective steps K1 to K4, the characteristics such as the wear characteristics largely change due to the change in rigidity, ie, the uneven wear resistance It can be evaluated.

  The inventors have found that parameter P having a high correlation between the uneven wear resistance performance by the wear testing machine M of the present embodiment and the uneven wear resistance performance by actual vehicle running through various experiments in such a determination step K4. Found out. The details of the test method of each uneven wear resistance test are as follows.

<Uneven wear resistance test with wear tester M>
Nine types of tires T having different formulations were prepared, and each rubber sample G1, G2 was collected from the tread portion Ta of each tire T. And the roller body 5 which adhered each rubber sample G1 and G2 was prepared, was made to contact the roller body 5 on the grindstone surface 4 under the following conditions, was pressed, and it was made to rotate so as to run 4000 m. Then, after the end of traveling, the wear amount of the rubber sample G was measured. The parameter P includes the ratio (f2 / f1) of the wear amount f1 of the first rubber sample G1 to the wear amount f2 of the second rubber sample G2, and in the present embodiment, the ratio (f2 / f1) is used. . The tire has a tread pattern. The main specifications are as follows.
Tire size: 195/65 R15
Dimension of roller body 5 (d1 × W1): 74 × 18 mm
Rubber sample G thickness t1: 2.0 mm
Width Wa of first rubber sample G1: 9 mm
Width Wb of second rubber sample G2: 18 mm
Load F: 40 N
Slip angle α: 6 degrees

<Uneven wear resistance test by running a car>
A tire T having the same specification as the tire T from which the rubber sample G was taken out was mounted on four wheels of a passenger car having a displacement of 2000 cc, and traveled a test course on a dry asphalt road surface for 6000 km under the following conditions. After running, the test driver visually confirmed the occurrence of uneven wear of the land portion of the tread portion Ta, and evaluated the uneven wear resistance performance by sensory. The test results are shown in Table 1.
Rim size: 15 × 6 J
Internal pressure: 230 kPa
Speed: 60 to 120 km / h

  As shown in Table 1, it is understood that in the determination step K4, it is desirable to determine that the partial abrasion resistance is good as the ratio (f2 / f1) that is the parameter P is closer to 1. Further, it is understood that it is further desirable to determine that the non-uniform wear resistance is good in the determination step K4 when the ratio (f2 / f1) is in the range of 1 ± 0.2. Thereby, in the evaluation method of the present embodiment, evaluation can be made with good correlation with the uneven wear resistance performance in the actual vehicle running test. The experiment was conducted by changing the specifications of the rubber composition, tire size, slip angle α, load F, speed of actual vehicle travel, internal pressure, etc., but by making the ratio (f2 / f1) the parameter P, Similar high correlation was shown.

  The width Wa of the first rubber sample G1 and the width Wb of the second rubber sample G2 are not limited to those described above. When the width Wa of the first rubber sample G1 is larger than the width Wb of the second rubber sample G2, the width Wa of the first rubber sample G1 and the width Wb of the second rubber sample G2 are ratio (Wa / wb ) Is, for example, preferably more than 1 and 5 or less, and more preferably 1.5 to 3. Further, the width W of each rubber sample G may be the same as the width (not shown) in the tire axial direction of each land portion of the tread portion Ta.

  As described above, according to the evaluation method of the present embodiment, it is possible to determine whether the uneven wear resistance performance of the rubber member is good or bad. For this reason, for example, when a tire component, in particular, a tread rubber which is in contact with the road surface is manufactured by the same composition as a rubber member determined to be good by this evaluation method, a tire excellent in uneven wear resistance performance is manufactured. Can.

  Although the preferred embodiments of the present invention have been described above in detail, the present invention is not limited to the illustrated embodiments, and can be modified in various aspects.

G Rubber sample K1 Preparation step K2 Wear test step K3 Wear amount measurement step K4 Quality check step M Wear tester

Claims (10)

A method for evaluating the uneven wear resistance of a rubber member, comprising
Preparing a plurality of rubber samples including at least a first rubber sample and a second rubber sample having the same composition and different rigidity;
Performing a wear test on the first rubber sample and the second rubber sample under the same test conditions using a wear tester;
Measuring the amount of wear of the first rubber sample and the second rubber sample after the wear test;
Determining the quality of the uneven wear resistance of the rubber member based on a parameter related to the difference between the amount of wear of the first rubber sample and the amount of wear of the second rubber sample.
Evaluation method of uneven wear resistance of rubber member.   The evaluation method according to claim 1, wherein the rubber sample is collected from a tire.   The evaluation method according to claim 1, wherein the rubber sample is collected from a tread portion of a tire.   The evaluation method according to any one of claims 1 to 3, wherein the first rubber sample and the second rubber sample are in the form of a sheet having the same length and different widths.   The evaluation method according to any one of claims 1 to 4, wherein the wear tester is an indoor wear tester.   The evaluation method according to any one of claims 1 to 5, wherein the parameter includes a ratio of the amount of wear of the first rubber sample and the amount of wear of the second rubber sample.   The evaluation method according to claim 6, wherein in the determination step, it is determined that the partial abrasion resistance is good as the ratio is closer to 1.   The evaluation method according to claim 6 or 7, wherein in the determination step, the uneven wear resistance is determined to be good in the range of 1 ± 0.2 of the ratio. A process for producing a tire component with the same composition as a rubber member determined to be good by the evaluation method according to any one of claims 1 to 8,
Tire manufacturing method.   The tire manufacturing method according to claim 9, wherein the component of the tire is disposed in the tread portion.

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