JP2010249693A - On-ice friction tester and on-ice friction test method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-ice friction tester for simplifying a reference test, and correctly obtaining an aspect of an ice plate, and also to provide an on-ice friction test method using it. <P>SOLUTION: The on-ice friction tester is an on-ice friction tester for implementing a measurement by using a main test piece and a reference test piece, and comprises: a rotational shaft; the ice plate rotated on the rotational shaft; a holding means for holding the main test piece facing a surface of the ice plate; and at least one holding means for holding at least one reference test piece. The holding means is displaced along the rotational shaft in the direction in which the holding means approaches or is separated from the ice plate. The main test piece and the reference test piece contact with and separate from the same ice plate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an on-ice friction tester capable of more accurately grasping ice properties while simplifying a comparison test, and an on-ice friction test method using the same.

  It is strongly desired that tires that are widely used in snowy and cold regions have on-ice performance that can handle any snowy road surface. However, various developments have been made in order to realize a tire that exhibits versatile performance in a situation where the performance on the ice of the tire greatly changes depending on the properties of the ice on the snowy road surface.

  One of the indispensable elements for the development of such a tire is an on-ice friction tester for evaluating the on-ice performance of the tire (see, for example, Patent Document 1). Such an on-ice friction tester forms an ice plate and looks like an icy road, and measures the frictional force by pressing a rubber test piece against the icy road, and evaluates it by approximating an actual vehicle running test on the icy road. Again, the test results obtained depending on the properties of the ice plate can fluctuate greatly. Therefore, the ice condition at the time of the main test is usually grasped by performing measurement using a separate test piece, and the test piece is used. Measure.

JP 2001-356088 A

  However, in the measurement using such a testing machine, the ice plate melts due to friction with the rubber test piece and moisture is generated, and this freezes again with impurities such as rubber wear powder. If the test is conducted multiple times, the ice sheet properties will fluctuate greatly each time. Therefore, each time a test using this test piece is performed, the measurement using the comparison test piece must be performed before or after the test piece to estimate the state of the ice disk at the time of this test, and the test time is long. In addition, since the road surface condition during the main test is not directly measured, the evaluation accuracy may be reduced if a test over a plurality of times is approximated as an evaluation under the same conditions.

  Therefore, an object of the present invention is to provide an on-ice friction tester capable of more accurately grasping the properties of ice sheets while simplifying the comparison test, and an on-ice friction test method using the same.

In order to solve the above-mentioned problems, the present inventors have found an on-ice friction tester capable of performing measurement using a comparative test piece while performing measurement using the present test piece, and have completed the present invention. .
That is, the on-ice friction tester of the present invention is an on-ice friction tester that performs measurement using the present test piece and the contrast test piece,
An ice plate having a rotation axis and rotatable about the rotation axis;
Holding means for holding the test piece facing the surface of the ice plate and at least one holding means for holding at least one contrast test piece;
The holding means is displaced in a direction approaching and separating from the ice plate along the rotation axis to bring the main test piece and the contrast test piece into contact with and separated from the same ice plate. It is characterized by.

The ice plate is preferably an ice plate having a substantially annular shape.
Further, when the main test piece and the comparative test piece are brought into contact with the ice plate, the main test piece and the comparative test piece are separated from the center of the contact surface of the main test piece with the ice plate. It is preferable that the distance to the rotation axis and the distance from the center of the contact surface of the comparison test piece with the ice plate to the rotation axis of the ice plate are equal.
Furthermore, the measurement using the contrast test piece is preferably a measurement of a friction coefficient μs between the contrast test piece and the ice plate, and the measurement using the test specimen is It is preferable to measure the coefficient of friction μm between the ice plates.

Further, when the main test piece and the comparison test piece are brought into contact with the ice plate, the main test piece and the comparison test piece are arranged to face each other on a straight line perpendicular to the rotation axis of the ice plate. It is desirable that
When the main test piece and the comparison test piece are brought into contact with the ice plate, the area Sm of the contact surface of the main test piece with the ice plate, the pressing force Pm applied to the main test piece, the ice in the comparison test piece It is desirable that the area Ss of the contact surface with the board and the pressing force Ps applied to the comparison test piece satisfy the following formula (II-1):
Ps × Ss <Pm × Sm (II-1)
Furthermore, it is desirable to satisfy the following formula (II-2).
1/10 × Pm × Sm ≦ Ps × Ss ≦ 2/3 × Pm × Sm (II-2)

In addition, the maximum span length Am with respect to the direction perpendicular to the rotation direction of the ice plate at the contact surface with the ice plate in the test piece, and the rotation direction of the ice plate at the contact surface with the ice plate in the comparison test piece It is desirable that the maximum passing length As for the direction orthogonal to the following formula (III-1):
As ≦ Am (III-1)
Furthermore, it is desirable to satisfy the following formula (III-2).
As = Am (III-2)
Further, the maximum length Bm with respect to the rotation direction of the ice plate at the contact surface with the ice plate in the test piece, and the maximum transfer length with respect to the rotation direction of the ice plate at the contact surface with the ice plate in the comparative test piece. Bs may satisfy the following formula (IV-1):
Bs ≦ Bm (IV-1)
Furthermore, the following formula (IV-2) may be satisfied.
Bs <Bm (IV-2)

A water film measuring device may be arranged in front of or behind the comparison test piece with respect to the rotation direction of the ice plate and closer to the comparison test piece than the main test piece. Well, a water film removing device is arranged in front of or behind the comparison test piece with respect to the rotation direction of the ice plate, and closer to the comparison test piece than the main test piece. Also good.
Further, a friction coefficient measuring system having a vertical load measuring instrument and a tangential force measuring instrument for measuring the friction coefficients μs and μm may be provided.
The on-ice friction test method of the present invention is characterized in that, when evaluating the on-ice performance of rubber, using the above-mentioned on-ice friction tester, the measurement using the test piece is performed while the measurement using the test piece is performed. And

  In the present specification, the term “test specimen” means a rubber specimen used in the main test in order to collect evaluation data that approximates the performance test on ice by running a tire, and the contrast specimen is more accurate. It means a rubber test piece used for grasping the ice state at the time of the main test in order to collect data from the test piece.

  According to the on-ice friction tester of the present invention, the on-ice property at the time of the main test can be grasped instantaneously, and the measurement result is not affected by fluctuations on the on-ice property even if the on-ice friction test is performed multiple times. Can be obtained. In addition, if the on-ice friction tester of the present invention is used, it is not necessary to perform a separate comparison test every time this test is performed to estimate the on-ice properties at the time of the test, and the on-ice friction test method in which the test process is simplified. Can be realized.

It is a partial section outline line side view showing the whole friction tester on ice concerning the present invention. It is the partial cross-section approximate line front view and side view which show the holding means which hold | maintains this test piece and a comparison test piece, and this test piece and a comparison test piece which are hold | maintained at this. FIG. 3A is a perspective view of the main test piece Xm having a substantially cylindrical shape, and FIG. 3B is a main test piece Xm having a substantially cubic shape. It is the upper surface schematic diagram of the ice board 2 by which this test piece Xm and contrast test piece Xs are arrange | positioned. It is the upper surface schematic diagram of the ice board 2 by which this test piece Xm and contrast test piece Xs are arrange | positioned.

Hereinafter, the present invention will be described in detail with reference to the drawings as necessary.
FIG. 1 is a schematic configuration diagram of an on-ice friction tester according to the present invention, and the tester is provided with a temperature control (−20 ° C. to 40 ° C.) provided with a refrigeration device (not shown) and a heating device (not shown). The ice plate 2 is arranged in a horizontal position in the central portion of the temperature-controlled room 1 capable of being), and the ice plate 2 is moved around the rotary shaft 2a by the ice plate drive motor 3 through the speed reducer 4 at a desired speed. Rotate if possible. The ice plate 2 is not particularly limited as long as it has the rotation shaft 2a, but is preferably an ice plate having an annular shape. Moreover, the ice board 2 is not restricted to what is arrange | positioned with a horizontal attitude | position, For example, you may arrange | position with a vertical attitude | position.

  Here, the ice plate 2 supplies the water cooled by the cooler in the chiller 6 to the ice plate frame 2b having a substantially bowl shape, and the cooling water in the frame surrounds almost the entire tester. The cooling air cooled to a desired temperature by the cold air generator 5 can be fed into the temperature-controlled room 1 to be frozen, thereby forming the ice plate 2 at an ice temperature corresponding to the cooling air temperature. Maintained.

  FIG. 2 is a schematic view showing holding means for holding the test piece Xm and the contrast test piece Xs, and the test piece Xm and the contrast test piece Xs held on the holding means. Here, the test piece Xm is detachably held at one end of the sample shaft 7m on the ice plate 2 side by the sample shaft 7m disposed in a horizontal posture above the ice plate 2. Similarly, the test piece Xs is detachably held at one end of the sample shaft 7 s on the ice plate 2 side by the sample shaft 7 s arranged in a horizontal posture above the other of the ice plate 2. FIG. 2 shows an example in which the held main test piece Xm and the contrast test piece Xs are arranged so as to face each other around the rotation axis 2a above the ice plate 2. However, the present invention is not limited to this. Instead, it is sufficient that at least the main test piece Xm and the comparative test piece Xs held are arranged to face the surface of the ice plate 2. The on-ice friction tester of the present invention only needs to have at least one holding means for holding the above-mentioned comparison test piece Xs and at least one comparison test piece Xs, and a plurality of these may be provided. .

  In FIG. 2, the shapes of the test piece Xm and the contrast test piece Xs are substantially cylindrical Xm (a) as shown in the partially enlarged view of FIG. It is not limited, and as shown in the partially enlarged view of FIG. 3 (b), it may have a substantially cubic shape Xm (b) in which some opposing surfaces have an isosceles trapezoid shape. . The shape of the contrast test piece Xs can also be the same shape as the test piece Xm. When the shape of the test specimen Xm (or the contrast test specimen Xs) is substantially cylindrical, for example, as shown in FIG. 3A, the test specimen Xm (a) (or the contrast test specimen) is taken by the sample holder 30m (a). Xs (a)) is held, and when the shape of the test piece Xm (or the contrast test piece Xs) is substantially cubic, for example, as shown in FIG. Xm (b) (or the contrast specimen Xs (b)) is held. Since the holding means for holding the test piece Xm and the holding means for holding the contrast test piece Xs have the same configuration, the holding means will be described below with a focus on the configuration of the holding means for the test piece Xm. To do.

  On the other hand, a sample shaft driving motor 10m for rotating the test piece Xm at a desired peripheral speed is attached to the other end of the sample shaft 7m, particularly when the test piece Xm exhibits a substantially cylindrical shape Xm (a). Alternatively, a torque meter 11m for measuring the torque around the axis generated on the sample shaft 7m may be disposed in the middle portion thereof. At this time, the test piece Xm (a) having a substantially cylindrical shape can be rotated and oscillated or freely rolled by the action of the sample shaft 7m. It should be noted that the sample shaft 7m does not necessarily need to be rotated, and the test piece Xm disposed at one end of the sample shaft is not used as in the case where the shape of the test piece Xm is substantially a cube (Xm (b)). You may function as a guide at the time of pressing on the ice board 2 hold | maintaining.

When the test piece Xm (a) is rotated by the action of the sample shaft 7m, it is desirable to control the rotation speed so that a constant slip ratio is added. In general, when the rotation speed of the ice plate 2 is Vr (m / sec) and the rotation speed of the test piece Xm (a) is v (m / sec), the slip ratio (%) is expressed by the following formula (A). The
Slip rate (%) = (Vr−v) / Vr × 100 (A)
Here, in the present invention, the ice slip 2 is adjusted so that the slip ratio is usually −20% to + 20% (excluding 0%), preferably −10% to + 10% (excluding 0%). It is desirable to appropriately control the rotational speed V and the rotational speed v of the test piece Xm (a).

  In the case where the ice plate 2 is arranged in a horizontal posture, in the example of the holding means that moves in the direction of approaching and separating from the ice plate 2 along the rotation shaft 2a, the sample shaft 7m (and the sample shaft drive) The motor 10m) is supported by the back plate 12m on the back side. An example of the reciprocating drive means attached to the fixed frame 13m is guided by a linear guide (not shown) disposed on the back side of the lifting plate 12m with respect to the lifting plate 12m. With the action of the test unit elevating cylinder 14m as described above, displacement of the holding means in the direction of approaching and separating from the ice plate 2 along the rotating shaft 2a is realized. The weight of the sample shaft 7m (and the sample shaft drive motor 10m / torque meter 11m) may be offset by the weight applied to the lift plate 12m with a balance weight (not shown) via a wire, for example.

  The test piece Xm is held facing the surface of the ice plate 2 by the holding means as described above, and at the time of the test, the holding means is displaced in the direction of approaching the ice plate 2 along the rotation axis 2a. Thus, the test piece Xm is brought into contact with the ice plate 2, and a desired pressing load is applied to the test piece Xm by the reduction cylinder 19m. A vertical load sensor, a three-component force meter, or the like may be interposed between the reduction cylinder 19m and the sample shaft 7m so that the pressing load can be changed as desired. Further, it is preferable to select the arrangement position of the reduction cylinder 19m so that the center of the pressing force acting on the test piece Xm is the center of the contact width to the ice plate 2.

  Further, here, the rod 15m of the test unit elevating cylinder 14m attached to the fixed frame 13m is moved together with the sample shaft 7m and the elevating plate 12m together with the pressing plate 19m which is displaced in the direction of approaching and separating from the ice plate 2, and the intermediate plate 20m Install through. Here, for example, when the test piece Xm is brought into contact with the ice plate 2, the holding means is moved along the rotary shaft 2a by lowering the rod 15m of the elevating cylinder 14m to the lowest end together with the sample shaft 7m. 2 is displaced in the direction of approaching. At this time, the restraint between the upper part of the sample shaft lifting guide shaft 21m and the intermediate plate 20m is released, and the sample shaft 7m and the lifting plate 12m are in a free state. At this time, the elevating cylinder 14m is fixed by air at the lowermost end, so that a required pressing load can be applied by the reduction cylinder 19m.

  When the test piece Xm is substantially cubic (Xm (b)), the sample shaft 7m may be directly connected to the reduction cylinder 19m. As shown in FIG. 3, the test piece has any shape. Is also in contact with and pressed against the ice plate 2 in the Y direction (direction approaching the ice plate 2).

  On the other hand, when the test piece Xm is separated from the ice plate 2, the upper portion of the sample shaft elevating guide shaft 21m and the intermediate plate 20 are moved by raising the rod 15m of the elevating cylinder 14m to the uppermost end together with the sample shaft 7m. The holding means is separated from the ice plate 2 along the rotation axis 2a.

  By configuring in this way, the test unit elevating cylinder 14m allows the sample shaft 7m holding the main test piece Xm to be moved to the rising position where the main test piece Xm is largely separated from the ice plate 2, and the main test piece Xm. Can be displaced between a position where the ice plate 2 is in contact with the ice plate 2, and the reduction cylinder 19m presses the test piece Xm against the ice plate 2 with a required force, and the pressing force is required. It can be increased or decreased depending on

  The holding means for holding the contrast test piece Xs shown in FIG. 2 has the same configuration as the holding means for the main test piece Xm. At the start of the test, the main test is held facing the surface of the ice plate 2. The piece Xm is brought into contact with the ice plate 2 which is rotated around the rotation axis 2a while being cooled to a desired temperature by the sample cylinder 7m and the reduction cylinder 19m arranged on the upper part of the test piece Xm, and the desired force The comparison test piece Xs pressed against the surface of the ice plate 2 and held against the surface of the ice plate 2 is brought into contact with the same ice plate 2 by the reduction cylinder 19s disposed above the sample shaft 7s and the comparison test piece Xs. It contacts and is pressed with a desired force.

  The on-ice friction tester of the present invention comprises holding means for holding the test piece Xm and at least one holding means for holding at least one comparison test piece Xs as described above. The test piece can be brought into contact with the same ice plate 2 by being displaced in a direction close to the ice plate 2 along the rotation axis 2a of the ice. During the measurement using the test piece Xm, the measurement using the comparative test piece Xs can be performed. When frictional heat or the like is generated by the contact between the test piece Xm and the ice plate 2, a water film is generated on the ice plate 2 due to the water generated by melting a part of the ice plate 2, or the contrast test piece Xs. The moisture re-freezes with impurities such as rubber wear powder caused by the above, so that the properties of the ice plate 2 may be greatly changed. However, using the friction tester on ice of the present invention, the measurement using the test specimen Xs during the measurement using the test specimen Xm enables the ice disk during the measurement using the test specimen Xm. 2 can be grasped instantaneously, and measurement can be performed with the properties of the ice plate 2 in the test piece Xm and the contrast test piece Xs made uniform.

  In general, the properties of the ice plate 2 may vary depending on factors such as the amount of water film generated due to contact between the test piece and the ice plate, the surface roughness, the temperature, and the generation of impurities including rubber wear powder caused by the test piece. Among these factors, the generation of impurities particularly affects the measurement result because the properties of the ice plate largely fluctuate due to the re-freezing of the impurities together with the moisture on the ice plate. However, if the on-ice friction tester of the present invention is used, it is not necessary to separately perform the measurement using the comparative test piece Xs before or after the measurement using the test piece Xm, and the ice plate 2 by performing repeated tests. As a result, it is possible to reduce the influence of fluctuations in the properties and the generation of rubber wear powder as much as possible, thereby shortening the entire test time and simplifying the entire test process.

  Further, in the friction tester on ice of the present invention, when the test piece Xm and the contrast test piece Xs are brought into contact with the ice plate 2 by the holding means having the test unit elevating cylinder 14m (14s) and the reduction cylinder 19m (19s), It is desirable to arrange the test piece Xm and the contrast test piece Xs so that the distances from the center of the contact surface of the test piece with the ice plate 2 to the rotation axis 2a of the ice plate 2 are equal. In this case, specifically, as shown in the top view of the ice plate 2 in FIG. 4A, the center of the contact surface Cm of the test piece Xm with the ice plate 2 is Om, and the ice plate 2 of the contrast test piece Xs. When the center of the contact surface Cs with Os is Os, the distance dm from Om to the rotating shaft 2a is equal to the distance ds from Os to the rotating shaft 2a. That is, Om and Os are positioned on a concentric circle centered on the rotating shaft 2a, and when the ice plate 2 rotates around the rotating shaft 2a, the contact surfaces Cm and Cs of the main test piece Xm and the contrast test piece Xs are changed. The same trajectory is drawn on the same ice plate 2. By doing in this way, the influence which this test piece Xm has by the wrinkle formed when the contrast test piece Xs contacts and presses the ice board 2 can be reduced as much as possible.

  Further, it is more desirable that the test piece Xm and the contrast test piece Xs are arranged so as to face each other on a straight line R orthogonal to the rotation axis 2a of the ice plate 2 while satisfying the above conditions. In this case, specifically, as shown in the top view of the ice plate 2 in FIG. 4B, the distance dm from the center Om of the contact surface Cm of the test piece Xm with the ice plate 2 to the rotating shaft 2a is compared. The distance ds from the center Os of the contact surface Cs of the test piece Xs with the ice plate 2 to the rotating shaft 2a is equal, and the center Om and the center Os are located on a straight line R perpendicular to the rotating shaft 2a. It will be. By doing in this way, this test piece Xm and the contrast test piece Xs will be spaced apart from each other at the maximum and placed above the ice plate 2, and the test piece Xs is generated by contacting and pressing the ice plate 2. It is easy to reduce the influence on the test specimen Xm due to the water film and rubber abrasion powder.

  As specific examples of dm and ds shown in FIG. 4, for example, when the ice plate 2 has a substantially annular shape with a diameter of 100 to 200 cm, dm and ds are preferably 45 to 95 cm.

When the friction coefficient is μ, the area of the contact surface (Cm or Cs) of the test piece is S (m ² ), and the pressing force applied to the test piece is P (N / m ² ), the load W (N) is generally It is represented by the following formula (I-1), and the frictional force F (N) is represented by the following formula (I-2).
W = P × S (I-1)
F = μ × W (I-2)
Here, the amount of water generated on the ice plate increases and decreases in proportion to the friction force F. Therefore, if the load W is suppressed as much as possible, the amount of water generated before and after the test piece can be further reduced. It is possible to effectively suppress fluctuations in the properties of the board. Therefore, in order to reduce the influence of the contrast specimen Xs on the specimen Xm as much as possible, the area of the contact surface Cm of the specimen Xm with the ice plate 2 is Sm, and the pressing force applied to the contrast specimen Xs is Pm. When the area of the contact surface Cs of the contrast test piece Xs with the ice plate 2 is Ss and the pressing force applied to the contrast test piece Xs is Ps, it is desirable that these satisfy the following formula (II-1).
Ps × Ss <Pm × Sm (II-1)
More preferably, the following formula (II-2)
1/10 × Pm × Sm ≦ Ps × Ss ≦ 2/3 × Pm × Sm (II-2)
And most preferably the following formula (II-3)
Ss <Sm (II-3)
It is desirable to satisfy.

  By satisfying such a relationship, it is possible to reduce the amount of moisture generated by the comparison test piece Xs contacting and pressing the ice plate 2 while contacting the same ice plate 2. Fluctuations in ice properties during testing can be effectively suppressed. In addition, since it is possible to avoid the load W (= μ × Ps × Ss) applied to the contrast test piece Xs from being reduced more than necessary, it is possible to reduce the variation in the measurement results obtained. Further, for example, it is possible to avoid that the value of the friction coefficient μ (μs and μm) between each test piece and the ice plate 2 cannot be measured.

In addition, when the ice plate 2 is a substantially annular shape having a diameter of 100 to 200 cm, the area Sm of the contact surface Cm of the test piece Xm with the ice plate 2 is usually 1 to 50 cm ² , preferably 1 to 10 cm ² . The area Ss of the contact surface Cs of the contrast test piece Xs with the ice plate 2 is usually 1 to 50 cm ² , preferably 1 to 10 cm ² .

Further, as shown in FIG. 5, the maximum passing length with respect to the direction orthogonal to the rotation direction Y of the ice plate 2 at the contact surface Cm in FIG. 4 is Am, and orthogonal to the rotation direction Y of the ice plate 2 at the contact surface Cs. Assuming that the maximum passing length in the direction to be taken is As, it is desirable to satisfy the following formula (III-1):
As ≦ Am (III-1)
It is more desirable to satisfy the following formula (III-2).
As = Am (III-2)
In addition, the said maximum delivery length means the longest delivery length among the delivery lengths with respect to the direction orthogonal to the rotation direction Y in the said contact surface.

  Normally, when the test piece is lowered by the action of the reduction cylinder 19 and pressed against the ice plate 2 rotated about the rotation axis 2a, one piece of the ice plate 2 is caused by friction generated between the test piece and the ice plate 2 in contact therewith. The portion gradually melts, and a ridge that forms a recess is formed on the ice plate 2. Therefore, when the test is performed a plurality of times, it is the bottom surface of the recess that the test piece actually contacts the ice plate 2. Here, if Am of the test piece Xm and As of the contrast test piece Xs satisfy the above formula (III-1), the test specimen Xm is embedded in the recess of the bowl formed in the ice plate 2 by the contrast test piece Xs. Since the main test piece Xm comes into contact with the ice plate 2, both the main test piece Xm and the contrast test piece Xs can be brought into contact with the bottom surface of the recess. Further, when the above formula (III-2) is satisfied, the test piece Xm comes into contact with the ice plate 2 in a state of being fitted in the recess of the bag formed by the contrast test piece Xs. It is more desirable because both the test piece Xm and the contrast test piece Xs can be brought into contact with the bottom surface of the recess more reliably. By doing in this way, it becomes possible to reduce the influence which this test piece Xm receives by the wrinkles which the contrast test piece Xs forms, contacting with the same ice board 2.

In addition, when the area Sm of the contact surface Cm with the ice plate 2 of the test piece Xm is 1 to 50 cm ² and the area Ss of the contact surface Cs with the ice plate 2 of the contrast test piece Xs is 1 to 25 cm ² , The maximum extension length Am at the surface Cm is usually 1 to 7 cm, preferably 1 to 5 cm, and the maximum extension length As at the contact surface Cs is usually 1 to 7 cm, preferably 1 to 5 cm.

In particular, in the case where both the test specimen Xm and the contrast test specimen Xs are substantially cubic as shown in FIG. 3B, to further reduce the influence of the test specimen Xm by the wrinkles formed by the contrast test specimen Xs. When the maximum passing length with respect to the rotation direction Y of the ice plate 2 on the contact surface Cm is Bm, and the maximum passing length with respect to the rotation direction Y of the ice plate 2 on the contact surface Cs is Bs, the above formula (III− It is desirable to satisfy the following formula (IV-1) in addition to 1) or (III-2)
Bs ≦ Bm (IV-1)
It is more desirable to satisfy the following formula (IV-2).
Bs <Bm (IV-2)
In addition, the said maximum delivery length means the longest delivery length among the delivery lengths with respect to the rotation direction Y in the said contact surface.

  When the test piece is a substantially cube shown in FIG. 3 (b), the corner of the substantially cube comes into contact with the wall surface of the ridge formed by the friction between the test piece and the ice plate 2, and rubber wear powder is generated. There is a possibility that the properties of the ice plate 2 may fluctuate greatly. In addition, the wall surface of the heel is damaged by such contact, and the shape of the concave portion of the heel changes to a curved shape, and the bottom surface of the smooth concave portion exhibits a curved surface, so that the test piece cannot be sufficiently brought into contact with the bottom surface of the concave portion. There is also a fear. However, if the maximum length Bm at the contact surface Cm of the test piece Xm and the maximum length Bs at the contact surface Cs of the contrast test piece Xs satisfy the above formula (IV-1), the same ice plate 2 is able to prevent the corner portion of the contrast test piece Xs from contacting the wall surface of the bowl while suppressing the maximum passing length Bs while being in contact with the ice 2. And the test piece can be reliably brought into contact with the bottom surface of the concave portion of the ridge. Further, since the area Ss of the contact surface Cs of the comparison test piece Xs can be reduced, the amount of water generated by the contact of the comparison test piece Xs as shown in the above formulas (I-1) to (I-2) can be reduced. Can also be reduced. Furthermore, if the above formula (IV-2) is satisfied, these effects can be further ensured.

  In addition, the maximum extension length Am at the contact surface Cm of the test piece Xm with the ice plate 2 is 1 to 7 cm, and the maximum extension length As at the contact surface Cs of the test piece Xs with the ice plate 2 is In the case of 1 to 7 cm, the maximum delivery length Bm at the contact surface Cm is usually 1 to 7 cm, preferably 1 to 5 cm, and the maximum delivery length Bs at the contact surface Cs is usually 1 to 5 cm, preferably Is 1 to 3 cm.

  As a measurement using the above-mentioned contrast test piece Xs, the measurement of the friction coefficient μs between the contrast test piece Xs and the ice plate 2 is preferable. By measuring the friction coefficient μs, the amount of water that increases or decreases in proportion to the frictional force F expressed by the above formula (I-2) is grasped when the comparison specimen Xs and the ice plate 2 are in contact with each other. It is possible to accurately grasp the properties of the ice plate 2 at the time of this test. Further, by adjusting the pressing force Ps applied to the comparison test piece Xs, it is possible to appropriately adjust the amount of water generated. Similarly, as the measurement using the test piece Xm, the measurement of the friction coefficient μm between the test piece Xm and the ice plate 2 is preferable, and the test piece Xm is selected according to the measurement result of the friction coefficient μm. It is possible to appropriately adjust the amount of water generated by the contact between the ice plate 2 and the ice plate 2. The device arranged for measuring the friction coefficient μs or the friction coefficient μm is not particularly limited. For example, a friction coefficient measurement system having a vertical load measuring instrument and a tangential force measuring instrument is preferable. As mentioned.

  In addition, the water film measuring device is placed in front of or behind the above-mentioned comparison specimen Xs with respect to the rotation direction Z around the rotation axis 2a of the ice plate 2 and closer to the comparison specimen Xs than the main specimen Xm. It is desirable to arrange. By doing so, it is possible to instantly grasp the water film formed on the ice plate 2 by the moisture generated in front of or behind the comparison test piece Xs due to the friction between the comparison test piece Xs and the ice plate 2. Therefore, it is possible to accurately grasp the fluctuation of the test data of the test piece Xm that can be influenced by the water film. Here, when the shape of the contrast test piece Xs is a substantially cubic shape as shown in FIG. 3B, moisture generated behind the contrast test piece Xs with respect to the rotation direction Z due to this shape. The water film formed by the moisture generated in the front of the contrast test piece Xs has little influence on the measurement result because the water film formed by the water generated in the rear has little influence on the measurement result. In order to influence the measurement result, it is more effective to dispose the water film measuring device at a position in front of the contrast test piece Xs with respect to the rotation direction Z, for example, at a position Q shown in FIG.

  Furthermore, a water film removing device is provided at a position in front of or behind the above-mentioned comparative test piece Xs with respect to the rotation direction Z around the rotation axis 2a of the ice plate 2 and closer to the comparative test piece Xs than the main test piece Xm. It is desirable to have it. The water film removing device usually has a water film removing function such as a brush or a sponge, and an extra water film formed on the ice plate 2 in front of or behind the contrast test piece Xs by arranging such a device. It is possible to obtain more accurate test data. Here, when the shape of the contrast test piece Xs is a substantially cubic shape as shown in FIG. 3B, moisture generated behind the contrast test piece Xs with respect to the rotation direction Z due to this shape. The water film formed by the moisture generated in the front of the contrast test piece Xs has little influence on the measurement result because the water film formed by the moisture generated in the rear has little influence on the measurement result. In order to affect the measurement result, it is more effective to dispose the water film removing device at a position in front of the contrast test piece Xs with respect to the rotation direction Z, for example, at the position Q shown in FIG. By doing in this way, it becomes easy to always keep the surface of the ice board 2 in front of the test piece Xm in the rotation direction Z in a dry state, and more stable test data can be obtained.

  When both the water film measuring device and the water film removing device are arranged, the contrast test piece Xs is located at a position behind the water film measuring device with respect to the rotation direction Z regardless of the shape of the contrast test piece Xs. It is desirable to arrange the water film removing device. Thus, the properties of the ice plate 2 from which the excess water film has been removed by the water film removing device can be grasped by the water film measuring device immediately before the measurement using the test piece Xm.

1: constant temperature chamber 2: ice plate 2a: rotating shaft 2b: ice frame 3: ice plate drive motor 4: speed reducer 5: cold air generator 6: cold water machine 7m, 7s: sample shaft 10m, 10s: sample shaft drive motor 11m, 11s: Torque meter 12m, 12s: Elevating plate 13m, 13s: Fixed frame 14m, 14s: Test unit elevating cylinder 19m, 19s: Reduction cylinder 20m, 20s: Intermediate plate 21m, 21s: Sample shaft elevating guide shaft R: Ice Straight line orthogonal to the rotation axis 2a of the board 2 Xm: Main test piece Xs: Comparison test piece Y: Direction of the test piece close to the ice plate 2 Z: Direction of rotation of the ice plate 2 around the rotation axis 2a Q: Water Suitable placement position for membrane measuring device or water membrane removing device

Claims (16)

An on-ice friction tester that performs measurement using this test piece and a contrast test piece,
An ice plate having a rotation axis and rotatable about the rotation axis;
Holding means for holding the test piece facing the surface of the ice plate and at least one holding means for holding at least one contrast test piece;
The holding means is displaced in a direction of approaching and separating from the ice plate along the rotation axis to bring the main test piece and the contrast test piece into contact with and separated from the same ice plate. A friction tester on ice.   The on-ice friction tester according to claim 1, wherein the ice plate is an ice plate having a substantially annular shape.   When the main test piece and the comparison test piece are brought into contact with the ice plate, the main test piece and the comparison test piece are rotated from the center of the contact surface of the main test piece with the ice plate. 3. The friction on ice according to claim 1, wherein the distance from the center of the contact surface of the comparison specimen to the ice disk and the distance from the rotation axis of the ice disk are equal to each other. testing machine.   The on-ice friction tester according to any one of claims 1 to 3, wherein the measurement using the comparison test piece is a measurement of a friction coefficient μs between the comparison test piece and the ice plate.   The on-ice friction tester according to claim 1, wherein the measurement using the main test piece is a measurement of a friction coefficient μm between the main test piece and the ice disk.   When the main test piece and the comparison test piece are brought into contact with the ice plate, the main test piece and the comparison test piece are arranged to face each other on a straight line perpendicular to the rotation axis of the ice plate. The on-ice friction tester according to any one of claims 1 to 5. When the main test piece and the comparison test piece are brought into contact with the ice plate, the area Sm of the contact surface of the main test piece with the ice plate, the pressing force Pm applied to the main test piece, the ice in the comparison test piece The on-ice friction tester according to any one of claims 1 to 6, wherein the area Ss of the contact surface with the board and the pressing force Ps applied to the comparison test piece satisfy the following formula (II-1).
Ps × Ss <Pm × Sm (II-1) The on-ice friction tester according to claim 7, wherein the area Sm, the pressing force Pm, the area Ss, and the pressing force Ps satisfy the following formula (II-2).
1/10 × Pm × Sm ≦ Ps × Ss ≦ 2/3 × Pm × Sm (II-2) The maximum span length Am with respect to the direction orthogonal to the ice disk rotation direction at the contact surface with the ice plate in the test piece, and the rotation direction of the ice disk at the contact surface with the ice plate in the comparison test piece. The on-ice friction tester according to claim 7 or 8, wherein a maximum passing length As with respect to a direction to satisfy the following formula (III-1):
As ≦ Am (III-1) The friction tester on ice according to claim 9, wherein the maximum delivery length Am and the maximum delivery length As satisfy the following formula (III-2).
As = Am (III-2) The maximum passing length Bm with respect to the ice disk rotation direction at the contact surface with the ice plate in the test piece, and the maximum transfer length Bs with respect to the ice disk rotation direction at the contact surface with the ice plate in the contrast test piece. Satisfy | fills following formula (IV-1), The friction tester on ice in any one of Claims 7-10 characterized by the above-mentioned.
Bs ≦ Bm (IV-1) The on-ice friction tester according to claim 11, wherein the maximum delivery length Bm and the maximum delivery length Bs satisfy the following formula (IV-2).
Bs <Bm (IV-2)   A water film measuring device is disposed in front of or behind the contrast test piece with respect to the rotation direction of the ice plate and closer to the contrast test piece than the main test piece. The on-ice friction tester according to any one of claims 1 to 12.   A water film removing device is disposed in front of or behind the contrast test piece with respect to the rotation direction of the ice disk and closer to the comparison test piece than the main test piece. The on-ice friction tester according to any one of claims 1 to 13.   The friction test on ice according to any one of claims 4 to 14, further comprising a friction coefficient measurement system having a vertical load measuring instrument and a tangential force measuring instrument for measuring the friction coefficients µs and µm. Machine.   In evaluating the on-ice performance of rubber, using the on-ice friction tester according to any one of claims 1 to 15, the measurement using the comparison test piece is performed while the measurement using the main test piece is performed. A friction test method on ice characterized by the above.

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