JP5534587B2 - Rubber testing machine - Google Patents

Description

  The present invention relates to a rubber testing machine, and more particularly, to a rubber testing machine for performing a wear test of vulcanized rubber, and more particularly to a rubber testing machine for performing a wear test of vulcanized rubber for automobile tires.

  Conventionally, a lambone tester is known as an apparatus for performing a vulcanized rubber abrasion test (JIS K6264). The Lambourn tester rotates a test piece made of a disc-shaped vulcanized rubber and a disc-shaped grindstone or a simulated road surface at an independently determined number of revolutions while rotating the test piece on the outer circumference of the grindstone or the simulated road surface. The test pieces are worn by being pressed against the surface and slipping each other, and the amount of wear is measured after a certain time.

  Also, in the Lambourn tester, the friction force applied to the test piece when the rubber test piece is rotated so as to have a constant slip rate with respect to the grindstone or the simulated road surface is detected, and each detected friction force and the slip rate are detected. A method of measuring the degree of rubber wear from the friction energy defined based on the above is also known (see Patent Document 1). In this measurement method, both the road surface and rubber are formed so as to be rotatable about an axis, are brought into contact with each other on curved surfaces, and friction energy (= slip distance) obtained approximately from the detected longitudinal force and slip ratio X Friction force) to determine the degree of rubber wear.

  On the other hand, as a rubber testing machine capable of evaluating a more accurate degree of rubber wear, a rubber testing machine that reproduces a behavior when an actual product such as a tire is worn has been proposed ( Patent Document 2). According to this technology, by creating an adhesive state and a slip state of rubber when the rubber and the road surface come into contact with each other, it is possible to more accurately reproduce the wear state when the rubber is actually worn. .

JP-A-11-326169 JP 2009-198276 A (Claims etc.)

  According to the rubber testing machine according to Patent Document 2, the behavior of rubber when an actual product such as a tire is worn is accurately reproduced, and the measured value of the rubber wear degree corresponding to the actual wear result is accurately obtained. It is possible to obtain. However, even in the rubber testing machine of Patent Document 2, since there is a limit to the reproducible tire wear situation, it is possible to evaluate an accurate degree of rubber wear that is closer to the wear situation during actual vehicle travel, and more to actual vehicle travel. The realization of a rubber testing machine capable of reproducing a wear form that is close to the occasion has been demanded.

  Accordingly, an object of the present invention is to solve the above-mentioned problems and to reproduce the behavior of rubber during actual wear with higher accuracy. An object of the present invention is to provide a rubber testing machine capable of responding to the results with higher accuracy.

  As a result of intensive studies, the present inventors have found the following points. In other words, when an actual product such as a tire is worn, the contact time between the rubber and the road surface is determined by the size and structure of the tire. For example, two tires with different tread rubber types are run under the same conditions. In this case, the grounding time does not vary greatly. However, when a rubber test piece is tested with a conventional Lambone tester or a tester such as those shown in Patent Documents 1 and 2, the type of rubber as shown in FIG. For example, when the hardness is changed, the contact time varies greatly, and in such a conventional rubber testing machine, it is considered that there is a limit to the behavior of the tire tread block that can be reproduced in this respect. This is because the actual product has a pneumatic structure made of a composite material, whereas the rubber test piece has a structure directly connected to a rotating shaft or the like of the testing machine.

  From this point of view, the present inventors have further studied, and as a result, the rubber tester is provided with a mechanism for adjusting the contact time between the rubber test piece and the road surface, etc. The test can be performed under the conditions, and it has been found that the wear situation when the rubber is actually worn can be reproduced with higher accuracy, and the present invention has been completed.

That is, the present invention is a rubber testing machine for testing a rubber test piece by pressing a rubber test piece on a grindstone or a pseudo road surface,
A control mechanism for a contact time between the rubber test piece and the grindstone or the pseudo road surface is provided, and the control mechanism for the contact time includes a measuring means for measuring a time during which the rubber test piece and the grindstone or the pseudo road surface are in contact with each other. And, the pressing speed of the rubber test piece is controlled so that the measured contact time is equal to the set value.

  In the present invention, the rubber test piece is pressed against the grindstone or the pseudo road surface, and the relative position of the rubber test piece and the grindstone or the pseudo road surface in the direction perpendicular to the pressing direction is changed. It is preferable to provide adhesion and / or slip to the grindstone or simulated road surface. Moreover, it is preferable that the rubber testing machine of this invention is equipped with the control mechanism of the pressing load of the said rubber test piece.

In the present invention, it is preferable that the contact time control mechanism controls the position of the rubber test piece in the pressing direction so as to form a sine wave, a modified sine wave, or a pulse wave shape with respect to the time axis. In the present invention, the position of the rubber test piece in the pressing direction can be controlled using an actuator and a motor.

  The rubber testing machine of the present invention is an abrasion testing machine that wears the rubber test piece between the grindstone or the simulated road surface and measures the frictional force between the grindstone or simulated road surface and the rubber test piece. It can be suitably used. Further, in the present invention, it is preferable that the positions of both the rubber test piece and the grindstone or the pseudo road surface are varied independently of each other, thereby reproducing the phenomenon from the contact of the tire tread block to the kicking-out. be able to.

  According to the present invention, the above configuration makes it possible to more accurately reproduce the behavior of rubber when an actual product such as a tire is worn, thereby measuring the degree of rubber wear and the form of wear to be measured. Thus, it has become possible to realize a rubber testing machine that can more accurately correspond to actual wear results.

It is a schematic explanatory drawing which shows one structural example of the rubber testing machine of this invention. It is a flowchart which shows the flow of control of the contact time of a rubber test piece and a grindstone or a pseudo road surface. It is a graph which shows the locus | trajectory of the fluctuation | variation of the position in the pressing direction of a rubber test piece ((a) sine wave, (b) deformation | transformation sine wave or (c) pulse wave). It is explanatory drawing which shows transition of the contact state between a rubber test piece and a grindstone or a pseudo road surface. It is a graph which shows the relationship between the pressing speed of a rubber test piece, and the contact time with respect to a grindstone or a pseudo road surface in the comparison with the hard rubber and soft rubber from which hardness differs relatively. It is explanatory drawing which shows an example of the link mechanism for converting the rotational motion of a motor into the vertical motion of a rubber test piece.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In FIG. 1, the schematic explanatory drawing of one structural example of the rubber testing machine of this invention is shown. As shown in the figure, the rubber tester of the present invention tests the rubber test piece 1 by pressing the rubber test piece 1 against a grindstone or a pseudo road surface (hereinafter also simply referred to as “road surface”) 11.

  The rubber testing machine of the present invention is characterized in that a control mechanism for the contact time between the rubber test piece 1 and the road surface 11 is provided. Thus, the contact time between the rubber test piece 1 and the road surface 11 can be controlled without depending on the shape and rubber physical properties of the rubber test piece 1, and the test can be performed under the same grounding time conditions. . Therefore, according to the rubber testing machine of the present invention, the rubber test piece 1 can be tested in a state where the wear situation when the rubber is actually worn is reproduced with higher accuracy, that is, different rubber types. Can be subjected to the test under the same conditions as in actual use.

  In the present invention, the specific structure of the contact time control mechanism is not particularly limited. For example, as shown in FIG. 2, the pressing speed of the rubber test piece 1 was measured, assuming that the contact time control mechanism includes a measuring unit that measures the time for which the rubber test piece 1 and the road surface 11 are in contact with each other. A method of controlling the contact time (measured value) and the preset contact time (set value) to be equal can be used. Here, the contact time between the rubber test piece 1 and the road surface 11 corresponds to the contact time in an actual product tire. In this case, first, the pressing load of the rubber test piece 1 against the road surface 11 and the contact time between the rubber test piece 1 and the road surface 11 are input as representative values to start the operation of the rubber tester. Next, the actual contact time between the rubber test piece 1 and the road surface 11 is measured, the obtained measurement value is compared with the set value of the contact time, and if the measured value and the set value do not match, the pressing speed is set. Repeat the adjustment. Then, the wear test is started when the measured value matches the set value. By controlling the pressing speed in this way, it is possible to always perform the test under the same grounding time condition without depending on the shape of the rubber test piece 1 and the rubber physical properties.

  Further, in the contact time control mechanism, as shown in FIGS. 3A to 3C, the position of the rubber test piece 1 in the pressing direction is a sine wave, a modified sine wave, or a pulse wave shape with respect to the time axis. It is good also as what controls to make. Since the position of the rubber test piece 1 in the pressing direction can be controlled by using an actuator and a motor, the rubber test piece 1 can be controlled to have a sine wave as shown by controlling the actuator and motor with high accuracy. It can be controlled to move up and down along the modified sine wave or pulse wave. Also, by making the link mechanism for converting the rotational movement of the motor into the vertical movement of the rubber test piece 1, the vertical movement of the rubber test piece 1 can be changed into a sine wave and a modified sine as shown in the figure. It can be along a wave or pulse wave. For example, if a link mechanism as shown in FIG. 6A is used, the locus of the rubber test piece follows a sine wave shown in FIG. If a link mechanism as shown in FIG. 6B is used, the locus of the rubber test piece follows the modified sine wave shown in FIG. In the figure, reference numerals 21A and 21B denote cams, 22 denotes a motor shaft, 23 denotes a jig (holder), and 24 denotes a guide rail. The cams 21A and 21B are rotated along with the rotation of the motor shaft 22, and the jig is rotated. By moving 23 up and down along the guide rail 24, the rubber test piece 1 can be moved up and down in accordance with a sine wave or a modified sine wave.

  In the rubber testing machine of the present invention, in order to perform the test under the same conditions without depending on the shape of the rubber test piece 1 and the rubber physical properties, in addition to the control mechanism for the pressing speed of the rubber test piece 1, the rubber test piece 1 It is preferable to provide a pressing load control mechanism. The shape of the rubber test piece 1 is controlled by controlling the contact time between the rubber test piece 1 and the road surface 11 for each rubber test piece 1 while the pressing load of the rubber test piece 1 on the road surface 11 is set to a constant value. Regardless of the physical properties of the rubber, the test conditions can always be constant, and it is possible to obtain test results that more accurately reflect actual wear conditions.

  In the rubber testing machine shown in the figure, a grindstone or a pseudo road surface 11 is configured to be reciprocally movable in a plane along a guide rail 12, and the rubber test piece 1 is fixed by a jig (holder) 13 to be guided. It is configured to reciprocate in the direction perpendicular to the road surface 11 along the rail 14. Thereby, since the position of both the rubber test piece 1 and the road surface 11 can be changed independently of each other, the rubber test piece 1 is pressed against the road surface 11 and the rubber test piece 1 and the road surface 11 are pressed in the pressing direction. The change in the relative position in the orthogonal direction can be controlled independently, and these road surfaces 11 are reproduced so as to reproduce the operation when the tread block of the tire is stepped on and then kicked out (grounding to kicking). And the movement and position of both rubber specimens 1 can be controlled.

  In the present invention, in particular, the rubber test piece 1 is pressed against the road surface 11 by changing the relative position of the rubber test piece 1 and the road surface 11 in the direction perpendicular to the pressing direction. It is preferable to provide adhesion and / or slip. By applying adhesion and / or slip to the rubber test piece 1, the behavior of the rubber test piece 1 at the time of wear can be reproduced in a state closer to the actual condition including the adhesion state and the slip state. Therefore, according to such a rubber testing machine, for example, a rubber abrasion test (or rubber friction test, hereinafter referred to as “abrasion test” and “friction test” in the present invention) that can accurately trace the wear behavior of the tread rubber during actual vehicle running. This makes it possible to predict the degree of rubber wear (amount of wear) of the tread rubber in an actual vehicle with high accuracy.

  Here, the behavior of the rubber test piece 1 when the test of the rubber test piece 1 is performed using the rubber testing machine shown in FIG. 1 will be described. FIG. 4 is an explanatory diagram showing an example of the transition of the contact state between the rubber test piece 1 and the road surface 11. In the illustrated example, the rubber test piece 1 is pressed against the road surface 11, and the position of the road surface 11 is moved rightward in the horizontal direction while moving the position downward in the vertical direction. That is, immediately after the rubber test piece 1 moves downward in the vertical direction and comes into contact with the road surface 11, the rubber test piece 1 adheres to the road surface 11 while shearing and follows the movement of the road surface 11 (in the drawing). (B), (c)). Thereafter, when the limit of the shear deformation of the rubber test piece 1 is exceeded, slip occurs together with adhesion between the rubber test piece 1 and the road surface 11 ((d) in the figure). Further, when the moving direction of the rubber test piece 1 is changed to the upper side in the vertical direction, the rubber test piece 1 and the road surface 11 are not sticked and only slip ((e) in the figure). As described above, by sticking and / or slipping the rubber test piece 1 while changing the position of both the rubber test piece 1 and the road surface 11 independently of each other, the rubber test piece 1 is subjected to shear deformation. Can do. In this case, although not shown, only the rubber test piece 1 is moved with respect to the road surface 11 to give the rubber test piece 1 adhesion and / or slip to the road surface 11 and to cause shear deformation. Is possible.

  In the rubber abrasion test by the rubber testing machine of the present invention, specifically, the rubber test piece 1 is worn between the road surface 11 and the frictional force between the road surface 11 and the rubber test piece 1 is measured. Can be done. In the present invention, not only the wear amount can be measured, but also the adhesive state and the sliding state when the rubber test piece 1 is worn as described above can be reproduced, and the slip rate is constant as in the conventional method. Instead, it is possible to directly measure the sliding distance and the frictional force generated between the rubber test piece 1 and the road surface 11 at the time of wear with the slip ratio equal to or close to that of the tire. The defined wear energy can be calculated directly. Further, since the rubber test piece 1 can be grounded and worn against the road surface 11 by the same mechanism as that of the tire, it is possible to significantly improve the actual vehicle predictability as a result.

  In the rubber testing machine of the present invention, the grindstone or the simulated road surface 11 is formed of any material and surface properties such as various asphalts, concrete, sandpaper, wire nets, etc. according to the test conditions such as the intended road surface conditions. Is possible. In particular, it is preferable that at least a portion including a contact portion with the rubber test piece 1 is formed so as to be detachable so that it can be exchanged according to test conditions. Furthermore, in consideration of the temperature condition of the road surface, it is also preferable to form the contact portion of the road surface 11 with the rubber test piece 1 so that the temperature can be controlled.

  Moreover, as shown in the drawing, it is preferable that at least a contact portion of the grindstone or the pseudo road surface 11 with the rubber test piece 1 is formed in a flat shape. The rubber test piece 1 is also preferably formed so that the contact portion with the road surface 11 is flat as shown in the figure. When the circumferential surface is brought into contact with the road surface as in the sample of the Lambourn test, there will be a difference in the contact area between the soft rubber and the hard rubber. Even if the physical properties such as the hardness of the rubber specimen change, the contact area between the rubber and the road surface can be made constant. Also, the shape of the contact surface is different between the case where the rubber is in contact with the flat surface as in the actual road surface and the case where the rubber test piece is in contact with the curved road surface as in the Lambourn test machine. By making the road surface flat, it is possible to eliminate the influence of this curvature and reproduce the same state as when an actual rubber product contacts the road surface. Further, in the present invention, unlike the conventional method, there is no particular limitation on the shape of the ground contact portion with the road surface 11 of the rubber test piece 1. It is also possible to easily correspond to the elliptical shape of the ground.

  Further, although not shown in the drawings, in the rubber testing machine of the present invention, a load cell (for load detection) for measuring a vertical load applied to the rubber test piece 1 is provided on the guide rail 12 for moving the road surface 11. A load cell (for detecting the frictional force) for measuring the frictional force applied to the rubber test piece 1 may be disposed on each of the guide rails 14 for moving the rubber test piece 1. Furthermore, as an observation means capable of observing the contact portion between the road surface 11 and the rubber test piece 1, a camera for observing the behavior of the rubber test piece 1 such as slip on the road surface 11, and the road surface of the rubber test piece 1. It is also possible to provide a three-component force sensor or the like for measuring a frictional force or a load applied to a contact portion with 11 at an appropriate place. Furthermore, in the rubber testing machine of the present invention, a laser or the like can be arranged as a measuring means for measuring the wear shape of the contact portion with the road surface 11 of the rubber test piece 1. When the test is performed, a wear powder removing means for removing the wear powder can be provided.

1 Rubber test piece 11 Whetstone or simulated road surface 12, 14, 24 Guide rail 13, 23 Jig (holder)
21A, 21B Cam 22 Motor shaft

Claims (8)

A rubber testing machine for testing a rubber test piece by pressing a rubber test piece on a grindstone or a simulated road surface,
A control mechanism for a contact time between the rubber test piece and the grindstone or the pseudo road surface is provided , and the control mechanism for the contact time includes a measuring means for measuring a time during which the rubber test piece and the grindstone or the pseudo road surface are in contact with each other. And the rubber testing machine which controls the pressing speed of this rubber test piece so that this measured contact time and set value may become equal .   Along with the pressing of the rubber test piece against the grindstone or the pseudo road surface, the relative position of the rubber test piece and the grindstone or the pseudo road surface in the direction perpendicular to the pressing direction is changed, and the rubber test piece is moved to the grindstone or the pseudo road surface. 2. The rubber testing machine according to claim 1, which provides adhesion and / or slip to the road surface.   The rubber testing machine according to claim 1, further comprising a control mechanism for a pressing load of the rubber test piece. The contact time of the control mechanism, the position in the pressing direction of the rubber test piece, a sine wave with respect to the time axis, any one of claims 1 to 3 for controlling so as to form a modified sine wave or pulse wave shape Rubber testing machine. The rubber testing machine as described in any one of Claims 1-4 which performs control of the position in the pressing direction of the said rubber test piece using an actuator and a motor. The abrading the rubber test piece with the grinding wheel or the simulated road surface, any one of claims 1 to 5 is a wear tester for measuring the frictional force between the whetstone or simulated road surface and the rubber test piece A rubber testing machine according to claim 1. The rubber testing machine according to any one of claims 1 to 6 , wherein positions of both the rubber test piece and the grindstone or the pseudo road surface are varied independently of each other. Said rubber test piece and both positions of the grinding wheel or the simulated road surface independently of one another by varying any one of claims 1 to 7 to reproduce the behavior to kicking the ground of the tread block of the tire Rubber testing machine.

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