JP2014190945A - Method and device of testing rubber abrasion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device of testing rubber abrasion that are capable of reproducing ground contact pressure with high precision in abrading a product such as a tire, while keeping the ground contact pressure of a rubber test piece constant with respect to a simulated road surface, without depending on an elasticity modulus of the rubber test piece, and thereby obtain a measurement result corresponding to an abrasion test result using a real tire with high precision.SOLUTION: In a method of testing rubber abrasion that includes abrasion of a rubber test piece by bringing it into contact with a simulated road surface which moves relatively to the rubber test piece, the rubber test piece is filled with a gaseous matter.

Description

  The present invention relates to a rubber wear test method and a rubber wear test apparatus, and more particularly to a wear test method and a rubber wear test apparatus for vulcanized rubber for automobile tires.

  Conventionally, an abrasion test of an elastic body, for example, a vulcanized rubber, has been widely performed for developing a rubber composition of a tire. The vulcanized rubber wear test is actually more accurate when it is mounted on a vehicle wheel (actual vehicle test). However, it requires labor and cost, and it is necessary to efficiently develop a rubber compound. There is a problem that it is not desirable.

In order to solve such a problem, a belt-like polishing body mounted between a pair of rollers is driven to rotate, and a sample is supported on a flat surface of the polishing body, and a constant load is applied to the sample by an air cylinder. However, a wear test apparatus that presses against the abrasive body is being studied (see, for example, Patent Document 1).
However, the rubber wear test method in which the sample is pressed against the abrasive body by this wear test apparatus has a problem that the road surface contact pressure behavior of the tire cannot be reproduced and the wear evaluation cannot be performed accurately.

Also, a wear test apparatus for performing a rubber wear test by pressing a rubber test piece against a grindstone or a simulated road surface, the rubber test piece being displaced with respect to the grindstone or the pseudo road surface, A wear test apparatus that gives adhesion and / or slip, wears a rubber test piece between a grindstone or a simulated road surface, and measures a frictional force between the grindstone or the simulated road surface and the rubber test piece has been studied ( For example, see Patent Document 2).
However, the rubber abrasion test method using this abrasion test apparatus is susceptible to temperature rise due to friction and the influence of abrasion powder, and there is a problem that the abrasion evaluation cannot be performed accurately.

Here, a method for evaluating the wear of a vulcanized rubber material alone in a room is defined in JIS K6264, and is widely known as a Lambourn wear test. In this Lambourn abrasion test, a rubber test piece made of a disc-shaped vulcanized rubber and a disc-shaped polishing wheel are rotated at independently determined rotational speeds while the rubber test piece is placed on the outer surface of the polishing wheel. While pressing with a predetermined pressing force, the rubber test pieces are worn by slipping each other, and the amount of wear is detected by measuring the mass of the rubber test pieces before and after the wear. The Lambourn tester used in the Lambourn abrasion test wears a test piece made of a disk-shaped vulcanized rubber and a disk-shaped grindstone or simulated road surface under a certain load while controlling an arbitrary stress and slip rate. The amount of wear after a certain time is measured (see, for example, Patent Documents 3 and 4).
However, the rubber test pieces used in these Lambourn abrasion tests have a large contact pressure when the rubber test pieces are pressed against the outer surface of the grindstone or simulated road surface with a constant load when the elastic modulus of the rubber test pieces is greatly different. It is difficult to perform a wear test with the contact pressure kept constant (change in the elastic modulus of the rubber specimen increases and the ground contact surface decreases, and the elastic modulus of the rubber test specimen decreases). There is a problem.
Therefore, there has been a strong demand for a new method that can perform a wear test with a constant ground pressure.

JP-A-6-34506 JP 2009-198276 A JP 2008-185475 A JP 2006-242697 A

  The present invention can maintain the contact pressure on the simulated road surface of the rubber test piece constant without depending on the elastic modulus of the rubber test piece, and can accurately reproduce the contact pressure when a tire or other product is worn. Therefore, an object of the present invention is to provide a rubber wear test method and a rubber wear test apparatus capable of obtaining a measurement result corresponding to an actual tire wear test result with high accuracy.

  As a result of intensive studies to achieve the above object, the present inventor can achieve the object by controlling the air pressure in the same manner as the tire by using a rubber test piece filled with gas. I found out. The present invention has been completed based on such findings.

  That is, the rubber abrasion test method of the present invention is the rubber abrasion test method including grounding and wearing the rubber test piece on a simulated road surface that moves relative to the rubber test piece. The gas is sealed in.

  The rubber wear test method of the present invention preferably further includes adjusting the pressure of the gas sealed in the rubber test piece so as to make the contact pressure of the rubber test piece with respect to the simulated road surface constant.

  Further, adjusting a distance between the rubber test piece and the simulated road surface, adjusting an angle of the rubber test piece with respect to the simulated road surface, controlling a stress or a slip ratio of the rubber test piece, and the like It is desirable to include.

  The simulated road surface may be any of a disk shape, a caterpillar (registered trademark) shape, and a planar shape.

  The rubber test piece may be manufactured using a bladder, or may be manufactured by expanding a ring-shaped rubber band vulcanized in advance by the bladder.

  The rubber test piece may be tubeless and filled with internal pressure, or may have a tube filled with internal pressure.

  The rubber wear test apparatus of the present invention comprises a rubber test piece, a pseudo road surface that moves relative to the rubber test piece, and a wear means that wears the rubber test piece by grounding it on the pseudo road surface. In the wear test apparatus, a gas is sealed in the rubber test piece.

  It is desirable to further include a pressure adjusting means for adjusting the pressure of the gas sealed in the rubber test piece so as to make the contact pressure of the rubber test piece with respect to the simulated road surface constant.

  Further, distance adjusting means for adjusting the distance between the rubber test piece and the simulated road surface, angle adjusting means for adjusting the angle of the rubber test piece with respect to the simulated road surface, and control for controlling the stress or slip ratio of the rubber test piece. It is desirable to further include means.

  According to the present invention, without depending on the elastic modulus of the rubber test piece, the ground pressure with respect to the simulated road surface of the rubber test piece is kept constant, and the contact pressure when a tire or other product is worn is reproduced with high accuracy. Accordingly, it is possible to provide a rubber wear test method and a rubber wear test apparatus capable of obtaining a measurement result corresponding to an actual tire wear test result with high accuracy.

It is the schematic plan view and schematic front view which show an example of the mechanism part of the rubber abrasion test apparatus of this invention. It is a block diagram which shows an example of the mechanism part of the rubber abrasion test apparatus of this invention.

Hereinafter, the present invention will be specifically described with reference to the drawings as necessary.
(Rubber wear test method)
The rubber abrasion test method of the present invention includes at least an abrasion process, and may further include a pressure adjustment process, a distance adjustment process, an angle adjustment process, a control process, and other processes as necessary.

<Wear process>
The wear process is a process in which a rubber test piece is grounded on the simulated road surface and worn.

-Simulated road surface-
There is no restriction | limiting in particular as a shape of the said pseudo road surface, According to the objective, it can select suitably, For example, disk shape, a caterpillar (trademark) shape, planar shape, etc. are mentioned.
There is no restriction | limiting in particular as a structure of the said simulated road surface, According to the objective, it can select suitably.
There is no restriction | limiting in particular as a magnitude | size of the said pseudo road surface, According to the objective, it can select suitably.
The material of the simulated road surface is not particularly limited and can be appropriately selected depending on the purpose.For example, various asphalts, concrete, sandpaper, wire mesh, etc., according to the test conditions such as the intended road surface conditions. It can be formed of any material and surface properties.

-Rubber test piece-
The rubber test piece is not particularly limited as long as a gas is sealed, and can be appropriately selected according to the purpose.
There is no restriction | limiting in particular as said gas, According to the objective, it can select suitably, For example, air, nitrogen, a carbon dioxide, argon etc. are mentioned.

There is no restriction | limiting in particular as a shape of the said rubber test piece, According to the objective, it can select suitably, For example, disk shape, plane shape, etc. are mentioned.
There is no restriction | limiting in particular as a structure of the said rubber test piece, According to the objective, it can select suitably, You may have a tube filled with internal pressure even if it is tubeless.
There is no restriction | limiting in particular as a magnitude | size of the said rubber test piece, According to the objective, it can select suitably.
The material of the rubber test piece is not particularly limited as long as it is a rubber material, and can be appropriately selected according to the purpose. However, it is a rubber composite material obtained by adding a vulcanizing agent in addition to a rubber component. Thus, vulcanized rubber suitable as a tire material is preferable.

The method for producing the rubber test piece is not particularly limited and can be appropriately selected according to the purpose. For example, a method of replacing a tread of a cart tire with a test piece, a rubber band pre-vulcanized by a bladder is used. And how to expand.
There is no restriction | limiting in particular as said bladder, According to the objective, it can select suitably, For example, the thing of Unexamined-Japanese-Patent No. 2010-30067 etc. are mentioned.
There is no restriction | limiting in particular as a shape of the said rubber band, According to the objective, it can select suitably, For example, a ring shape etc. are mentioned. There is no restriction | limiting in particular as a structure, a magnitude | size, and a material of the said rubber band, According to the objective, it can select suitably.

-Wear-
The abrasion is performed by bringing the rubber test piece into contact with a simulated road surface that moves relative to the rubber test piece.
The relative moving speed of the simulated road surface with respect to the rubber test piece is not particularly limited and may be appropriately selected depending on the purpose. However, the condition corresponding to the actual vehicle is preferably 0.01 m / second to 25 m / second. .

<Pressure adjustment process>
The pressure adjusting step is a step of adjusting the pressure of the gas sealed in the rubber test piece so as to make the contact pressure with respect to the pseudo road surface of the rubber test piece constant.

-Ground pressure-
There is no restriction | limiting in particular as said ground pressure, Although it can select suitably according to the objective, 50 kPa-1000 kPa are preferable as measurement conditions corresponding to a real vehicle.
In addition, as a grounding part measuring apparatus, a well-known thing can be used, for example, the grounding part measuring apparatus as described in patent 3277155 or patent 3406643 can be used.

-Gas pressure-
There is no restriction | limiting in particular as the pressure of the said gas, Although it can select suitably according to the objective, 50 kPa-1000 kPa are preferable.
If the pressure of the gas is outside the above range, it is difficult to reproduce the wear state in the actual vehicle because it differs from the internal pressure under the actual vehicle conditions.
There is no restriction | limiting in particular as the adjustment method of the said gas pressure, According to the objective, it can select suitably, For example, adjustment using an air valve etc. is mentioned.

<Control process>
The control step is a step of controlling the stress or slip rate of the rubber test piece.
There is no restriction | limiting in particular as stress of the said rubber test piece, According to the objective, it can select suitably.
There is no restriction | limiting in particular as a slip ratio of the said rubber test piece, According to the objective, it can select suitably.

(Rubber wear test equipment)
The rubber wear test apparatus of the present invention comprises the rubber test piece, the simulated road surface, and wear means, and further, as necessary, pressure adjustment means, distance adjustment means, angle adjustment means, control means, etc. The means is provided.

<Wearing means>
The wear means is means for causing the rubber test piece to wear by being grounded to the simulated road surface.
There is no restriction | limiting in particular as said abrasion means, According to the objective, it can select suitably.

<Pressure adjustment means>
The pressure adjusting means is a means for adjusting the pressure of the gas sealed in the rubber test piece so as to make the contact pressure of the rubber test piece with respect to the simulated road surface constant.
There is no restriction | limiting in particular as said pressure adjustment means, According to the objective, it can select suitably.

<Control means>
The control means is means for controlling the stress or slip rate of the rubber test piece.
There is no restriction | limiting in particular as said control means, According to the objective, it can select suitably.

Hereinafter, an example of the rubber abrasion test apparatus of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic plan view and a schematic front view showing an example of a mechanical part of a rubber wear test apparatus of the present invention, and FIG. 2 is a block diagram showing an example of a mechanical part of a rubber wear test apparatus of the present invention. is there.

  1 and 2, the rubber wear test apparatus 1 includes a disk-shaped rubber test piece 2, a disk-like simulated road surface 3, a simulated road surface rotating means 30 that rotates the simulated road surface 3, and a simulated road surface rotating means 30. A test piece rotating means 20 for rotating the rubber test piece 2 around an axis L2 parallel to the rotation axis L1 and a test piece pressing means 40 for pressing the rubber test piece 2 against the pseudo road surface 3 are provided. The rubber test piece 2 can be worn by rotating the pseudo road surface 3 and the rubber test piece 2 while pressing the peripheral surface of the rubber test piece 2 against the surface.

  Further, the rubber wear test apparatus 1 is provided with a test piece rotation control means 25 for controlling the test piece rotation means 20, and the test piece rotation control means 25 has a desired torque when rotating the rubber test piece 2. In this way, the test piece rotating means 20 can be controlled.

  Further, the rubber wear test apparatus 1 is provided with a simulated road surface rotation control means 35 for controlling the simulated road surface rotation means 30, and the simulated road surface rotation control means 35 has a desired rotation speed when rotating the simulated road surface 3. In this way, the pseudo road surface rotating means 30 can be controlled.

  Further, the rubber wear test apparatus 1 is provided with a pressure control means 45 for controlling the test piece pressing means 40, and the pressure control means 45 has a desired load for pressing the rubber test piece 2 against the simulated road surface 3. Thus, the test piece pressing means 40 can be controlled.

  Further, an output means 10 for outputting the torque control target value of the test piece rotation means 20 to the test piece rotation control means 25 is provided.

  Similarly, the output means 10 includes a rotation speed when the simulated road surface rotation control means 35 controls the rotation of the simulated road surface 3, and a pressure control means 45 when the rubber test piece 2 is pressed against the simulated road surface 3. A function of storing the load in the memory 11 or outputting the load to the simulated road surface rotation control means 35 and the pressure control means 45 is provided.

  In FIG. 2, reference numeral 12 denotes a CPU for controlling the output means 10, reference numeral 13 denotes a monitor indicating the state of the output means 10, and reference numeral 14 denotes a data input device such as a keyboard for inputting data. These are used to create command value data for each physical quantity stored in the output means 10 or change patterns of each physical quantity as test conditions when performing a wear test on the rubber test piece 2 (target and target). The time change (physical quantity time function Q (t)) of the physical quantity Q to be selected can be selected from those stored in the memory 11.

  Here, the test piece rotating means 20 is configured to include a bearing 21 that supports the rotating shaft 24 of the rubber test piece 2 and a motor 22 that rotationally drives the rotating shaft 24.

  The test piece rotation control means 25 can also be controlled so that the stress or slip rate of the rubber test piece 2 becomes desired in addition to a control method for controlling the torque when rotating the rubber test piece 2 as desired. It is comprised so that either of the control system which controls a torque, and the control system which controls a stress or a slip ratio can be selected.

  When performing control based on the stress or slip rate of the rubber test piece 2, the test piece rotation control means 25, with respect to the stress or slip rate of the rubber test piece 2 output from the output means 10, A target peripheral speed for rotating the rubber test piece 2 is obtained from the diameter of the simulated road surface 3 and the diameter of the rubber test piece 2, and the rotational speed of the rubber test piece 2 is controlled from this peripheral speed to a desired value. it can.

  Further, the simulated road surface rotating means 30 is configured to include a bearing 31 that supports the rotation shaft 34 of the simulated road surface 3 and a motor 32 that rotationally drives the rotation shaft 34. The control means 35 directly controls the rotational speed of the motor 32 by using a known technique for controlling the voltage input to the motor 32 so as to have a desired change pattern according to the type of the motor 32, and The rotation speed can be controlled.

  Also for the test piece pressing means 40, the movable base 43 to which the test piece rotating means 20 is attached, the guide mechanism 42 for guiding the movable base 43 in a direction in which the distance between the axis L 2 and the axis L 1 is changed, The pressure control means 45 adjusts the pressure of the hydraulic cylinder 41 so that the load on the simulated road surface 3 of the rubber test piece 2 becomes a desired value. It may be simple to have a configuration for direct control.

  In FIG. 1, reference numeral 5 denotes a common bed on which the simulated road surface rotating means 30 and the test piece pressing means 40 are mounted.

  As shown in FIG. 1, the cleaning roller 36 is disposed in the rubber abrasion test apparatus 1 so as to contact the peripheral surface of the simulated road surface 3, and the rubber powder adhering to the peripheral surface of the simulated road surface 3 is continuously removed. In addition, a rubber temperature monitor 9 for continuously monitoring the temperature of the peripheral surface of the rubber test piece 2 is provided, and the rubber temperature data is collected to contribute to the analysis of the wear state. The static electricity removing device 4 that sprays ions on the peripheral surface of the rubber test piece 2 is installed, and static electricity accumulated on the peripheral surface of the rubber test piece 2 is removed to prevent a fire from occurring.

  Further, a chamber 6 that covers at least the rubber test piece 2 is provided, and the ambient temperature of the rubber test piece 2 can be controlled so that the temperature of the rubber test piece 2 during the test becomes a desired value.

  Further, although not shown, the untested rubber test piece 2 is transferred from the untested rubber test piece mounting table to the test piece rotating means 20 and set, and the tested rubber test piece 2 is set to the test piece rotating means. A wear test using this apparatus can be automated by providing a rubber test piece transfer means that is removed from 20 and transferred to a tested rubber test piece mounting table.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.

(Preparation of rubber test piece A)
30 parts by mass of Asahi Carbon Co., Ltd. carbon black (Asahi # 78), 2 parts of stearic acid, 3 parts of zinc oxide, and 100 parts by mass of vulcanized rubber A (JSR Co., Ltd., SBR (product name: JSR0202)) having an elastic modulus of 10 MPa , Ouchi Shinsei Chemical Co., Ltd. anti-aging agent (Nocrack 6C) 1 part, Ouchi Shin Chemical Co., Ltd. vulcanization accelerator (Noxeller D) 0.5 part, Ouchi Shin Chemical Co., Ltd. A rubber test piece A having a cubic shape with a side of 5 cm was obtained by kneading 1 part of a sulfur accelerator (Noxeller CZ) and 1.5 parts of sulfur, followed by vulcanization.
In addition, the measuring method of the elasticity modulus performed the tension test based on JISK6251, measured by the tensile stress (M300) at the time of 300% elongation, and performed similarly below.

(Preparation of rubber test piece B)
100 parts by mass of vulcanized rubber B having an elastic modulus of 13 MPa (SBR (product name: JSR1500) manufactured by JSR Corporation), 50 parts by mass of carbon black (Asahi # 78) manufactured by Asahi Carbon Co., Ltd., 2 parts of stearic acid, zinc white 3 , Ouchi Shinsei Chemical Co., Ltd. anti-aging agent (Nocrack 6C) 1 part, Ouchi Shin Chemical Co., Ltd. vulcanization accelerator (Noxeller D) 0.5 part, Ouchi Shin Chemical Co., Ltd. A rubber test piece B was formed of a cube shape having a side of 5 cm and 1 part of a sulfur accelerator (Noxeller CZ) and 1.5 parts of sulfur, followed by vulcanization.

(Preparation of rubber test piece C)
A tire for a cart (outer diameter: 26 cm, tire width: 13 cm, tread width: 10 cm) was prepared, and a rubber test piece was obtained by pasting and vulcanizing the unvulcanized rubber of the vulcanized rubber A before vulcanization as the tread rubber. C was attached to the rim, and air was filled with an air valve until the internal pressure reached 80 kPa.

(Preparation of rubber test piece D)
A tire for a cart (outer diameter: 26 cm, tire width: 13 cm, tread width: 10 cm) was prepared, and a rubber test piece was obtained by attaching and vulcanizing the unvulcanized rubber before vulcanization of the vulcanized rubber B as a tread rubber. D was attached to the rim, and air was filled with an air valve until the internal pressure reached 80 kPa.

(Comparative Example 1)
The prepared rubber test piece A is attached to a rubber wear test apparatus (Bridgestone's prototype) having the structure shown in FIGS. 1 and 2, and the rubber test piece A is a simulated road surface (material: safety walk (Sumitomo 3M) with a load of 80N. A rubber abrasion test was conducted by controlling the pressure so as to be pressed against the product. Here, the ground pressure with respect to the pseudo road surface of the rubber test piece A was 80 kPa.
The contact pressure was measured with a Tire Pressure and Slip Plate, which is a contact pressure / displacement measuring device manufactured by Precision Measurement Co.

(Comparative Example 2)
In Comparative Example 1, a rubber abrasion test was conducted in the same manner as Comparative Example 1 except that the rubber test piece B was used instead of the rubber test piece A. Here, the ground pressure with respect to the pseudo road surface of the rubber test piece B was 70 kPa.

Example 1
In Comparative Example 1, a rubber abrasion test was performed in the same manner as in Comparative Example 1 except that the rubber test piece C was used instead of the rubber test piece A. Here, the ground pressure with respect to the pseudo road surface of the rubber test piece C was 80 kPa.

(Example 2)
In Comparative Example 1, a rubber abrasion test was performed in the same manner as in Comparative Example 1 except that the rubber test piece D was used instead of the rubber test piece A. Here, the ground pressure with respect to the pseudo road surface of the rubber test piece D was 80 kPa.

  From Table 1, in the rubber abrasion test methods of Comparative Examples 1 and 2, the contact pressure on the simulated road surface of the rubber test piece changes according to the change in the elastic modulus of the vulcanized rubber constituting the rubber test piece (10 MPa to 13 MPa). On the other hand, in Examples 1-2, the contact pressure with respect to the pseudo road surface of the rubber test piece is constant at 80 kPa even in the case where the elastic modulus of the vulcanized rubber constituting the rubber test piece is different. It can be seen that it is.

DESCRIPTION OF SYMBOLS 1 Rubber abrasion test apparatus 2 Rubber test piece 3 Simulated road surface 4 Static electricity removal apparatus 5 Common bed 6 Chamber 9 Rubber temperature monitor 10 Output means 11 Memory 12 CPU
13 Monitor 14 Data Input Device 20 Specimen Rotating Unit 21 Bearing 22 (for Rotating Specimen) Motor 22 (For Rotating Specimen) 24 Rotating Shaft 25 (for Rotating Specimen) Test Rotation Control Unit 30 Pseudo Road Surface Rotating Unit 31 Bearing 32 (for simulated road surface rotation) Motor 34 (for simulated road surface rotation) Rotating shaft 35 (For simulated road surface rotation) Pseudo road surface rotation control means 36 Cleaning roller 40 Test piece pressing means 41 Hydraulic cylinder 42 Guide mechanism 43 Movable Base 45 Press control means

Claims (4)

In a rubber wear test method including grounding and wearing the rubber test piece on a simulated road surface that moves relative to the rubber test piece,
A rubber wear test method, wherein gas is sealed in the rubber test piece.   The rubber wear test method according to claim 1, further comprising adjusting a pressure of a gas sealed in the rubber test piece so as to make a contact pressure of the rubber test piece with respect to the simulated road surface constant. . In a rubber abrasion test apparatus comprising: a rubber test piece; a pseudo road surface that moves relative to the rubber test piece; and a wear means that causes the rubber test piece to contact the pseudo road surface to wear.
A rubber wear test apparatus, wherein gas is sealed in the rubber test piece.   The rubber wear according to claim 3, further comprising a pressure adjusting means for adjusting a pressure of a gas sealed in the rubber test piece so as to make a ground contact pressure of the rubber test piece with respect to the simulated road surface constant. Test equipment.

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