JP2015004633A - Coarseness evaluation method for surface of ice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of easily and highly accurately evaluation coarseness of ice.SOLUTION: In the coarseness evaluation method for a surface of ice, a relation between standard ice surface coarseness and a friction coefficient μ is required between a standard rubber and standard ice at a fixed temperature T°C. The evaluation method includes the steps of: preparing test ice to evaluate surface coarseness; measuring the friction coefficient μ between the standard rubber and the test ice at the temperature T°C; and determining surface coarseness of the test ice. In the step of determining the surface coarseness of the test ice, the surface coarseness of the test ice is determined from the relation between the surface coarseness of the standard ice and the friction coefficient μ between the standard rubber and the standard ice on the basis of the friction coefficient μ of the test ice.

Description

  The present invention relates to a method for evaluating the roughness of an ice surface.

  As one of tire performance evaluations, tire grip performance on ice is evaluated. When evaluating the grip performance of a tire on ice, the roughness of the ice surface is an important parameter that affects the frictional force. For this reason, when evaluating the grip performance of the tire, it is necessary to grasp the roughness of the ice surface.

  As a method for evaluating the roughness of the ice surface, for example, a contact-type roughness meter is used. In the contact-type roughness meter, the roughness of the ice surface is evaluated by the tip of the stylus tracing the ice surface. A stylus with a large tip diameter cannot trace a fine uneven shape. A stylus with a large tip diameter is inferior in measurement accuracy. Even if a stylus with a small tip diameter is used, the ice surface is destroyed by the pressing force and frictional heat. Even with a stylus having a small tip diameter, it is difficult to accurately evaluate the roughness of the ice surface.

  Japanese Patent Application Laid-Open No. 2005-147752 proposes a method for evaluating roughness by diffusing a liquid on the surface of ice. In this method, the roughness of ice is evaluated from the liquid diffusion area. Japanese Utility Model Laid-Open No. 6-47810 proposes a method of evaluating roughness by reflecting leather light on the ice surface. In this method, the amount of reflected light is analyzed to evaluate the roughness of ice.

JP 2005-147752 A Japanese Utility Model Publication No. Hei 6-47810

  In the method in which the roughness is evaluated from the diffusion area of the liquid, it is difficult to evaluate if there is a crack on the ice surface. In addition, on the inclined surface, the liquid easily flows in the inclined direction, and accurate evaluation is difficult. In the method in which the roughness is evaluated from the reflected light of the leather light, the amount of the reflected light varies depending on the transparency of the ice. In addition, reflected light from the inside of the ice may be detected. In the evaluation of roughness by reflected light, the amount of reflected light varies depending on the ice condition. In the evaluation of roughness by reflected light, it is difficult to evaluate with high accuracy.

  An object of the present invention is to provide a method capable of easily and accurately evaluating the roughness of ice.

In the ice surface roughness evaluation method according to the present invention, the relationship between the surface roughness of the standard ice and the friction coefficient μ between the standard rubber and the standard ice at a constant temperature T ° C. is required.
This evaluation method is
Preparing test ice to be evaluated for surface roughness;
Measuring the friction coefficient μ between the standard rubber and the test ice at the temperature T ° C .;
Determining the surface roughness of the test ice.
In this step of determining the surface roughness of the test ice, based on the friction coefficient μ of the test ice, the relationship between the surface roughness of the standard ice between the standard rubber and the standard ice and the friction coefficient μ is used. The surface roughness has been determined.

  Preferably, the relationship between the surface roughness of the standard ice and the friction coefficient μ between the standard rubber and the standard ice is determined in the range of 20 μm to 300 μm in terms of 10-point average roughness (Rz).

  Preferably, the relationship between the surface roughness of the standard ice and the friction coefficient μ between the standard rubber and the standard ice is determined in the range of 3 μm or more and 50 μm or less in terms of arithmetic average roughness (Ra).

  Preferably, the temperature T ° C. is a constant temperature in the range of −10 ° C. to −1 ° C.

  In the ice surface roughness evaluation method according to the present invention, the ice surface roughness is evaluated with high accuracy from the viewpoint of the frictional force between rubber and ice. This highly accurate evaluation result of the surface roughness can be easily obtained.

FIG. 1 is a flowchart showing an ice surface roughness evaluation method according to an embodiment of the present invention. FIG. 2 is a flowchart showing a method for determining the relationship between the surface roughness of standard ice and the friction coefficient μ used in the evaluation method of FIG. FIG. 3A is an explanatory view showing the standard ice of FIG. 2 and its container, and FIG. 3B is an explanatory view showing the standard ice. FIG. 4 is an explanatory diagram of a method for measuring the friction coefficient μ of standard ice in the method of FIG. FIG. 5 is a graph showing the relationship between the surface roughness Rz of the standard ice surface and the friction coefficient μ determined by the method of FIG. FIG. 6 is a graph showing the relationship between the surface roughness Rz and the friction coefficient μ of the standard ice according to the example.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  As shown in FIG. 1, this ice surface roughness evaluation method includes the steps of preparing test ice, measuring the friction coefficient μ, and determining the surface roughness. .

  In the step of preparing test ice, test ice whose surface roughness is evaluated is prepared. In the step of measuring the friction coefficient μ, the friction coefficient μ of the test ice is measured. In the step of determining the surface roughness, the surface roughness of the test ice is determined from the measured friction coefficient μ. When determining the surface roughness of the test ice from the friction coefficient μ, the surface roughness of the test ice is determined based on the relationship between the surface roughness of standard ice described later and the friction coefficient μ.

  The flowchart of FIG. 2 shows a method for obtaining the relationship between the surface roughness of the standard ice and the friction coefficient μ. This method comprises the steps of preparing standard ice, measuring the friction coefficient μ, and determining the relationship between the surface roughness of the standard ice and the friction coefficient μ. The surface roughness of the test ice in FIG. 1 is determined from the relationship between the surface roughness of the standard ice and the friction coefficient μ determined by this method.

  With reference to FIG. 2, a method for determining the relationship between the surface roughness of standard ice and the friction coefficient μ will be described.

  In the step of preparing the standard ice, standard ice whose surface roughness is specified is prepared.

  A method of preparing this standard ice will be described with reference to FIGS. 3 (a) and 3 (b). A container 2 shown in FIG. 3A is prepared. The container 2 includes a bottom surface 4 having a substantially flat surface. The container 2 is made of metal, for example. This bottom surface 4 is shot blasted. By this shot blasting process, the roughness of the bottom surface 4 is adjusted. By this processing, for example, the bottom surface 4 is adjusted to a 10 μm roughness with a 10-point average roughness (Rz).

  As shown in FIG. 3A, ice 6 is made using the container 2. The shape of the bottom surface 4 of the container 2 is transferred to the surface 8 of the ice 6. As shown in FIG. 3B, the ice 6 is taken out from the container 2. In this way, the ice 6 is produced in which the surface 8 is transferred with a 10-point average roughness (Rz) of 10 μm roughness. The ice 6 is ice whose surface 8 is adjusted to 10 μm. Similarly, ice whose surface is adjusted to 10 μm average roughness (Rz), for example, 20 μm, 30 μm, 50 μm and 100 μm, is produced. In the present invention, ice whose surface is adjusted to a specific roughness in this way is referred to as standard ice. The ice 6 and the ice whose surface is adjusted to 20 μm, 30 μm, 50 μm, and 100 μm are all standard ice.

  In the step in which the friction coefficient μ is measured, the friction coefficient μ of the standard ice surface is measured. The coefficient of friction μ is measured in a constant temperature room at a constant temperature T ° C. This temperature T ° C. is a constant temperature set in a range from −10 ° C. to −1 ° C., for example. A friction coefficient measuring device is used for this measurement.

  FIG. 4 shows how the friction coefficient μ is measured. In this step, a standard rubber 10 is prepared. The standard rubber 10 is a rubber piece for sliding the ice surface to measure the friction coefficient μ. The standard rubber 10 is made of, for example, a crosslinked rubber that constitutes a tread surface of a tire.

  The standard rubber 10 is pressed against the surface 8 of the ice 6 with a load W. This standard rubber 10 slides on the surface 8 at a constant speed V. The frictional force F of the sliding standard rubber 10 is measured. This frictional force F is divided by the load W to calculate the friction coefficient μ. In this way, the friction coefficient μ of the surface 8 of the ice 6 is measured.

  Similarly to the ice 6, even with standard ice adjusted to 20 μm, 30 μm, 50 μm and 100 μm, the friction coefficient μ of the surface is measured. In this way, the coefficient of friction μ is measured on standard ice whose surfaces are adjusted to 10 μm, 20 μm, 30 μm, 50 μm and 100 μm, respectively.

  In the step of determining the relationship between the surface roughness of the standard ice and the friction coefficient μ, the relationship for specifying the surface roughness is determined in accordance with the specified friction coefficient μ.

  FIG. 5 shows an example of determining the relationship between the surface roughness of standard ice and the friction coefficient μ. The horizontal axis of FIG. 5 indicates the surface roughness of standard ice as a ten-point average roughness (Rz). The vertical axis represents the coefficient of friction μ between standard rubber and standard ice. In FIG. 5, the relational expression between the surface roughness (Rz) of the standard ice and the friction coefficient μ at the temperature T ° C. is shown as a second order approximation. In this example, determining the relationship between the surface roughness of the standard ice and the friction coefficient μ means obtaining a relational expression such as a quadratic approximate expression at a constant temperature. This relational expression is not limited to the quadratic approximate expression. This relational expression may be, for example, a cubic approximation expression or a higher order approximation expression.

  The ice surface roughness evaluation method of FIG. 1 will be described using the quadratic approximation shown in FIG. 5 as an example.

  In the step of preparing the test ice, ice for which the roughness of the surface is evaluated is prepared by this evaluation method.

  In the step of measuring the friction coefficient μ, the friction coefficient μ is measured in a constant temperature room at a constant temperature T ° C. As shown in FIG. 4, the standard rubber slides on the surface of the test ice in the same manner as the standard ice. The friction coefficient μ at this time is measured.

  In the step of determining the surface roughness, the corresponding ten-point average roughness (Rz) is determined based on the quadratic approximate expression of FIG. The ten-point average roughness (Rz) is determined by the surface roughness of the test ice.

  In the quadratic approximate expression shown in FIG. 5, the amount of change in roughness (Rz) with respect to the amount of change in friction coefficient μ is small in the range where the roughness (Rz) is small. The evaluation accuracy of roughness (Rz) decreases. From this viewpoint, the ten-point average roughness (Rz) is preferably such that the roughness (Rz) is 20 μm or more. On the other hand, in the range where the friction coefficient μ is large, the amount of change in roughness (Rz) with respect to the change in the amount of change in the friction coefficient μ is large. If this friction coefficient μ becomes too large, the evaluation accuracy of the roughness (Rz) decreases. From this viewpoint, the range of the ten-point average roughness (Rz) is preferably 300 μm or less.

  The frictional force between the ice surface and rubber varies with temperature. In this method, the change in frictional force is suppressed by evaluating at a constant temperature T ° C. By evaluating at a constant temperature T ° C., the roughness of the ice surface is evaluated with high accuracy.

  From the viewpoint of measuring the frictional force on the ice surface, this constant temperature T ° C is preferably -1 ° C or lower. According to this method, the roughness of the ice surface can be evaluated even if the temperature T ° C. is set at, for example, −40 ° C. or higher or −30 ° C. or higher. By setting the temperature T ° C. to −10 ° C. or higher, the surface roughness of ice can be easily evaluated without using a special cold-resistant apparatus.

  Further, even if a relational expression between the surface roughness of the standard ice and the friction coefficient μ is obtained in advance within a predetermined temperature range, for example, at a constant temperature of 1 ° C. within a range from −10 ° C. to −1 ° C. good. Thus, if the friction coefficient μ of the test ice is measured at any temperature of 1 ° C. within the predetermined temperature range, the surface roughness of the test ice can be evaluated.

  In this description, the ten-point average roughness (Rz) has been described as an example, but the surface roughness of ice can also be evaluated using the arithmetic average roughness (Ra). When evaluated by arithmetic average roughness (Ra), the range of the roughness (Ra) is preferably 3 μm or more. The range of the roughness (Ra) is preferably 50 μm or less.

  Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be construed in a limited manner based on the description of the examples.

[Test 1]
The relationship between the surface roughness of standard ice and the friction coefficient μ was determined by the method shown in FIG. Six types of containers made of SUS304 were prepared. The bottom of the container had a 10-point average roughness (Rz) and was shot blasted to 21 μm, 48 μm, 103 μm, 148 μm, 202 μm and 270 μm, respectively. In each of these containers, standard ice with a surface roughness was made.

  With respect to these six types of standard ice, the friction coefficient μ was measured at −5 ° C. The friction coefficient μ was measured using a “DF tester (dynamic friction tester)” manufactured by Nippon Sangyo Co., Ltd. as a friction coefficient measuring apparatus. The results are shown in Table 1.

  The relational expression between the surface roughness of these standard ices and the friction coefficient μ was obtained by a second order approximation. The result is shown in FIG.

  The ice surface roughness was evaluated by the ice surface roughness evaluation method shown in FIG.

[Test ice 1]
In the step where the ice was prepared, test ice was made at −5 ° C. The surface of the test ice was polished with a sandpaper of No. 100 (manufactured by Naniwa Abrasive Industry).

  In the step of measuring the friction coefficient μ, the friction coefficient μ of the test ice 1 was measured at a temperature of −5 ° C. as shown in FIG.

  In the step of determining the surface roughness, the corresponding roughness was obtained from the friction coefficient μ of the test ice 1 based on the quadratic approximation formula of FIG. The results are shown in Table 2.

[Test ice 2]
Test ice 2 was obtained in the same manner as test ice 1 except that the sandpaper used for polishing was changed to count 400. For the test ice 2, the surface roughness was obtained in the same manner as the test ice 1 based on the quadratic approximation formula of FIG. 6. The results are shown in Table 2.

[Test ice 3]
Test ice 3 was obtained in the same manner as test ice 1 except that the sandpaper used for polishing was changed to count 1200. For the test ice 3, the surface roughness was determined in the same manner as the test ice 1 based on the quadratic approximation formula of FIG. The results are shown in Table 2.

[Comparison test 1]
Similar to test 1, test ice 1-3 was prepared. About this test ice 1-3, the roughness of the surface was measured using the laser microscope (OLYMPUS "OLS4000"). The results are shown in Table 2.

[Comparison test 2]
Similar to test 1, test ice 1-3 was prepared. About this test ice 1-3, the roughness of the surface was measured using the contact-type roughness meter ("SJ-310" made by Mitutoyo). The results are shown in Table 2.

  As shown in Table 2, in Comparative Test 1, the roughness of the test ice with a small roughness could not be measured. Moreover, in the comparative test 2, the ice surface was destroyed by the tip of the contact stylus, and the roughness could not be measured accurately. In the evaluation method of Test 1, the roughness can be evaluated with higher accuracy than the evaluation methods of Comparative Tests 1 and 2. From this result, the superiority of the present invention is clear.

  The method described above can be widely applied as a method for evaluating the roughness of the ice surface with high accuracy in relation to the frictional force with rubber. By using ice whose surface roughness is evaluated by this method, the grip performance of rubber on ice can be evaluated with high accuracy.

2 ... Container 4 ... Bottom 6 ... Ice 8 ... Surface 10 ... Rubber

Claims (4)

The relationship between the standard ice surface roughness and the friction coefficient μ between the standard rubber and standard ice at a constant temperature T ° C. is required.
Preparing test ice to be evaluated for surface roughness;
Measuring the friction coefficient μ between the standard rubber and the test ice at the temperature T ° C .;
The surface roughness of the test ice is determined,
In the step of determining the surface roughness of the test ice, the surface of the test ice is determined from the relationship between the surface roughness of the standard ice between the standard rubber and the standard ice and the friction coefficient μ based on the friction coefficient μ of the test ice. A method for evaluating the roughness of an ice surface whose roughness has been determined.   The relationship between the surface roughness of the standard ice and the friction coefficient μ between the standard rubber and the standard ice is determined in a range of 20 μm to 300 μm in terms of a ten-point average roughness (Rz). Roughness evaluation method.   The relation between the surface roughness of the standard ice and the friction coefficient μ between the standard rubber and the standard ice is determined in the range of 3 μm to 50 μm in terms of arithmetic average roughness (Ra). Roughness evaluation method.   The roughness evaluation method according to any one of claims 1 to 3, wherein the temperature T ° C is a constant temperature in a range of -10 ° C to -1 ° C.

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