Friction test device and friction test method

Abstract

To provide a friction test device and a friction test method capable of suppressing variations in temperature of a road surface member.SOLUTION: A friction test device includes: a road surface member having a test road surface in contact with a test rubber body; liquid contact means for bringing a liquid into contact with the road surface member; and liquid temperature adjusting means capable of adjusting temperature of the liquid in contact with the road surface member. A friction test method includes: a liquid contact step of bringing the liquid into contact with the road surface member having the test road surface; a liquid temperature adjusting step of adjusting temperature of the liquid; and a measurement step of measuring a friction coefficient of the test rubber body by relatively moving the test rubber body with respect to the test road surface.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a friction testing apparatus and a friction testing method. [Background technology]

[0002] A friction tester is used to evaluate friction performance by pressing a rubber product or a test piece made of the same rubber against a test road member. The friction performance of a rubber product varies depending on the temperature of the road member that comes into contact with the rubber product, so it is necessary to adjust the temperature of the road member.

[0003] Patent Document 1 discloses a friction test device that adjusts the temperature of a road surface member by embedding a heater in the road surface member. Embedding a heater in the road surface member as in this friction test device carries the risk of damaging the road surface member. Even if the heater is installed on the bottom surface of the road surface member rather than embedded in the road surface member, heat is not easily transmitted to the road surface member, and variations in the temperature of the road surface member occur. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-233797 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present disclosure is to provide a friction testing device and a friction testing method that can suppress temperature variations in road surface components. [Means for solving the problem]

[0006] The friction testing apparatus of the present disclosure comprises a road surface member having a test road surface that contacts a test rubber body, a liquid contact means for bringing a liquid into contact with the road surface member, and a liquid temperature adjustment means capable of adjusting the temperature of the liquid in contact with the road surface member.

[0007] The friction testing method disclosed herein includes a liquid contacting step of bringing a liquid into contact with a road surface component having a test road surface, a liquid temperature adjusting step of adjusting the temperature of the liquid, and a measurement step of moving a test rubber body relative to the test road surface to measure the friction coefficient of the test rubber body. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing an example of a friction test device. [Diagram 2] FIG. 2 is a plan view showing the road surface member, the liquid contact means, and the liquid temperature adjustment means; [Diagram 3] Cross-sectional view of line III-III in Figure 2 [Figure 4] A diagram explaining the movement path of the test rubber body. [Diagram 5] Three-sided views of a test rubber body having a preferred shape [Figure 6] FIG. 1 shows an example of the side of the front edge of a test rubber body.

[0009] <Friction test equipment> First, an example of a friction test device 100 will be described with reference to Fig. 1 to Fig. 6. Note that in each drawing, the dimensional ratios in the drawing do not necessarily match the actual dimensional ratios, and the dimensional ratios between the drawings do not necessarily match either. Fig. 1 is a schematic diagram showing an example of the friction test device 100.

[0010] As shown in Fig. 1, the friction test device 100 can be used to evaluate the friction performance of a rubber product that comes into contact with a road surface. The rubber product is, for example, a tire or a shoe sole. The tire may be a pneumatic tire or a non-pneumatic tire.

[0011] The friction test device 100 comprises a road surface member 1 having a test road surface 1a that comes into contact with the test rubber body R, a liquid contacting means 2 that brings a liquid into contact with the road surface member 1, and a liquid temperature adjusting means 3 that can adjust the temperature of the liquid that comes into contact with the road surface member 1. With this configuration, the temperature of the road surface member 1 can be adjusted via the liquid by bringing the liquid adjusted by the liquid temperature adjusting means 3 into contact with the road surface member 1. This improves heat conduction to (from) the road surface member 1 compared to when temperature is adjusted by a heater, and can suppress temperature variation in the road surface member 1. In addition, since no processing of the road surface member 1 is required, there is no risk of damaging the road surface member 1 due to the creation of a hole for burying a heater, etc.

[0012] The test rubber body R may be a rubber product itself, or may be a test rubber piece made of the same rubber material as the rubber product. The test rubber body R is made of, for example, vulcanized rubber and has a flat surface Rf (see FIG. 5) that is pressed against the test road surface 1a. In the example of FIG. 1, the test rubber body R is formed in a rectangular parallelepiped shape, and its upper surface is bonded to a holder 4 described later. Therefore, the lower surface of the test rubber body R that faces the test road surface 1a becomes the flat surface Rf that is pressed against the test road surface 1a. The test rubber body R may be formed in an approximately hemispherical shape having the flat surface Rf.

[0013] The liquid is a substance that has a higher thermal conductivity than air and does not solidify during temperature adjustment. The liquid is preferably water (e.g., tap water or distilled water). This makes it possible to measure the friction coefficient (wet μ) of the test rubber body R on a wet road surface, which will be described later, with a liquid similar to rainwater. Furthermore, by using water as the liquid, it becomes easier to clean the test road surface 1a than when other liquids are used, making it easier to continue using the test road surface 1a. The liquid may be a mixture of water with alcohol or antifreeze, glycerin, etc. When measuring the wet μ of the test rubber body R, the liquid should have the same kinetic viscosity as water (20 degrees: 1.0034 (mm 2 / s)) is preferred.

[0014] FIG. 2 is a plan view showing the road surface member 1, the liquid contact means 2, and the liquid temperature adjustment means 3, with the test rubber body R and the like omitted. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. As shown in FIGS. 2 and 3, the road surface member 1 is preferably a member cut out of a part of an actual road surface (asphalt road surface or concrete road surface). For example, the road surface member 1 can be made by connecting a plurality of cut pieces of the actual road surface (not shown in FIG. 2). By making the road surface member 1 from the actual road surface pieces, the accuracy of the friction performance evaluation of the test rubber body R (see FIG. 1) can be improved. The road surface member 1 is not limited to the above, and may be a member in which aggregates used in actual road surfaces are fixed with an adhesive, an abrasive cloth, an anti-slip tape, a flat resin plate, a metal plate, or the like. It is preferable that the test road surface 1a is formed into a shape having irregularities.

[0015] The test road surface 1a (road surface member 1) is preferably formed in a shape having a longitudinal direction. The longitudinal length of the test road surface 1a is determined, for example, by the maximum moving speed of the test rubber body R. As the moving speed of the test rubber body R increases, the distance required for acceleration or deceleration increases, and therefore the length of the test road surface 1a increases. The length of the test road surface 1a is, for example, 0.5 m or more. In this embodiment, the road surface member 1 is formed in a rectangular shape in a plan view, but is not limited to this. For example, the road surface member 1 may be formed in a circular ring shape or the like.

[0016] It is preferable that the road surface member 1 is fixed to the liquid tank 21 described later via a metal plate 20 (see FIG. 3). This makes it easier to remove the road surface member 1 than when the road surface member 1 is directly fixed to the liquid tank 21, and makes it easier to replace the road surface member 1 when it deteriorates over time. The metal plate 20 is fixed to the bottom surface 1f of the road surface member 1, for example, by adhesion or the like.

[0017] The width Wd of the road surface member 1 is set appropriately depending on the performance of the liquid temperature adjustment means 3 and the number of lanes on which the test rubber body R slides. Reducing the number of lanes and narrowing the width Wd makes it easier to adjust the temperature of the road surface member 1, but the road surface member 1 will need to be replaced more frequently. On the other hand, increasing the number of lanes and widening the width Wd reduces the frequency of replacement of the road surface member 1, but it will take more time to adjust the temperature of the road surface member 1. For example, when the number of lanes is three, it can be used three times as much as when the number of lane is one, but it will take more time to adjust the temperature of the road surface member 1.

[0018] The liquid contacting means 2 brings the liquid Lq into contact with at least one surface of the road surface member 1. Specifically, the liquid contacting means 2 brings the liquid Lq into contact with one or more surfaces of the test road surface 1a, the side surfaces 1b to 1e, and the bottom surface 1f. In this embodiment, the liquid contacting means 2 brings the liquid into contact with the periphery of the road surface member 1. Specifically, the liquid contacting means 2 brings the test road surface 1a and the side surfaces 1b to 1e (other than the bottom surface 1f) into contact with the liquid Lq, but is not limited to this.

[0019] In this embodiment, the liquid contact means 2 includes a liquid tank 21 that stores the liquid Lq. The road surface member 1 is contained in the liquid tank 21. According to this configuration, by containing the road surface member 1 in the liquid tank 21, the liquid Lq and the road surface member 1 can be constantly in contact with each other when adjusting the temperature of the road surface member 1. This makes it easier to adjust the temperature of the road surface member 1, and further suppresses variations in the temperature of the road surface member 1.

[0020] The liquid tank 21 is formed in a shape that covers at least a part of the road surface member 1. In this embodiment, the liquid tank 21 is formed in a rectangular parallelepiped shape that covers the side surfaces 1b to 1e of the road surface member 1, but is not limited to this. The road surface member 1 is fixed to the bottom surface 21a of the liquid tank 21 (see FIG. 3) via the metal plate 20, but may be fixed to the side surfaces 21b, 21c, etc. of the liquid tank 21.

[0021] The liquid tank 21 is preferably provided with a heat insulating layer 211. With such a configuration, the influence of the room temperature in which the friction test device 100 is installed is reduced, and the liquid temperature of the liquid Lq stored in the liquid tank 21 is easier to adjust than when a liquid tank without a heat insulating layer is used. This makes it easier to adjust the temperature of the road surface member 1, and the temperature variation of the road surface member 1 can be further suppressed. In this embodiment, the heat insulating layer 211 is provided at a position that contacts the liquid Lq (inside the liquid tank 21). Specifically, the heat insulating layer 211 forms a part of the bottom surface 21a and the side surfaces 21b and 21c of the liquid tank 21. The heat insulating layer 211 is not limited to the above, and may be provided at a position that does not contact the liquid Lq (outside the liquid tank 21).

[0022] The heat insulating layer 211 has a groove 211a into which the metal plate 20 is fitted. The groove 211a extends along the X direction (the direction perpendicular to the paper surface of FIG. 3). The road surface member 1 is fixed to the groove 211a via the metal plate 20 by adhesion, bolting, or the like.

[0023] The liquid contact means 2 is preferably configured to be capable of forming a film of the liquid Lq on the test road surface 1a. According to such a configuration, by bringing the test road surface 1a into contact with the liquid Lq, it becomes easy to adjust the temperature of the test road surface 1a that is in contact with the test rubber body R of the road surface member 1. This makes it possible to suppress the variation in temperature of the test road surface 1a. In addition, since the liquid Lq penetrates into the unevenness formed on the test road surface 1a, a gap is unlikely to occur between the liquid Lq and the test road surface 1a, making it easier to adjust the temperature of the test road surface 1a than when a heater or the like is placed on the test road surface 1a. Furthermore, by forming a film of the liquid Lq on the test road surface 1a, it becomes possible to measure the wet μ of the test rubber body R. In this embodiment, the road surface member 1 is immersed in the liquid Lq, but this is not limited to this.

[0024] The thickness Th of the film of the liquid Lq (see FIG. 3) is, for example, 1 mm to 3 mm. In this embodiment, the depth of the liquid tank 21 is made greater than the height of the road surface member 1 to form a film of the liquid Lq on the test road surface 1a, but this is not limited to this. For example, the road surface member 1 may be embedded in the liquid tank 21 so that the test road surface 1a is flush with the bottom surface 21a of the liquid tank 21, to form a film of the liquid Lq on the test road surface 1a.

[0025] The liquid tank 21 is equipped with a rubber body 212 for preventing leakage of the liquid Lq. The rubber body 212 is provided on the upper side of the liquid tank 21. The upper surface of the rubber body 212 is provided at a position higher than the test road surface 1a. In this embodiment, the rubber body 212 is formed in a rectangular ring shape, and the rubber body 212 and the insulating layer 211 form side surfaces 21b, 21c of the liquid tank 21.

[0026] It is preferable that the liquid contacting means 2 brings the liquid Lq into contact with each of the side surfaces 1b, 1c of the road surface member 1 located at both ends of the short side of the test road surface 1a. With such a configuration, the road surface member 1 is sandwiched between the liquid Lq, making it easier to adjust the temperature of the road surface member 1. This makes it possible to further suppress variations in the temperature of the road surface member 1. In this embodiment, the liquid Lq is brought into contact with each of the side surfaces 1b, 1c of the road surface member 1 by providing gaps between each of the side surfaces 21b, 21c of the liquid tank 21 and each of the side surfaces 1b, 1c of the road surface member 1.

[0027] In this embodiment, the liquid temperature adjustment means 3 includes a refrigerant pipe 31 through which a refrigerant flows, a refrigerant temperature adjustment device 32 (see FIG. 2) capable of adjusting the temperature of the refrigerant, a temperature sensor (not shown) capable of measuring the temperature of the liquid or the test road surface 1a, and a control unit (not shown) for controlling the refrigerant temperature adjustment device 32. As the refrigerant, for example, a natural refrigerant such as water or carbon dioxide, or oil can be used. As the refrigerant temperature adjustment device 32, for example, a chiller (cooling water circulator) can be used.

[0028] The refrigerant pipe 31 is provided in the liquid tank 21 and submerged in the liquid Lq stored in the liquid tank 21. In this embodiment, the refrigerant pipe 31 is disposed in the liquid tank 21 in a substantially U-shape and submerged so as to pass near each of the side surfaces 1b to 1d of the road surface member 1, but is not limited to this. For example, the refrigerant pipe 31 may be disposed in the liquid tank 21 in a substantially I-shape.

[0029] The refrigerant pipes 31 are preferably submerged with a gap between them and the road surface member 1. This makes it possible to prevent the refrigerant pipes 31 from coming into contact with the road surface member 1, which would cause large variations in temperature of the road surface member 1. The refrigerant pipes 31 are preferably submerged to the same depth as the test road surface 1a. This makes it easy to adjust the liquid temperature near the test road surface 1a, and makes it possible to prevent variations in temperature of the test road surface 1a.

[0030] The temperature sensor may be a non-contact sensor (e.g., an infrared thermometer) or a contact sensor. In this embodiment, the temperature sensor is a liquid temperature sensor, but is not limited to this. When the temperature sensor is a liquid temperature sensor, it is preferable to measure the liquid temperature on the test road surface 1a with the temperature sensor. This makes it possible to measure a liquid temperature close to the temperature of the test road surface 1a. The measurement position of the liquid temperature by the temperature sensor is, for example, the center in the short side direction (width Wd direction) of the test road surface 1a.

[0031] The control unit controls the coolant temperature regulator 32 so that the coolant temperature becomes a predetermined temperature. The coolant temperature is determined, for example, by the following formula 1. T2 is the coolant temperature, T1 is the target temperature of the liquid Lq (for example, the surface of the liquid Lq located above the test road surface 1a), and T0 is the room temperature of the room in which the friction test device 100 is installed. α is a temperature coefficient, which is determined, for example, by the amount of liquid, the surface area of ​​the liquid surface in contact with the air and the road surface member 1, the diameter of the coolant pipe 31 (the surface area in contact with the liquid Lq), the thermal conductivity of each substance, and the heat insulating property of the liquid tank 21. Formula 1 can be used when the target temperature T1 is lower than the room temperature T0. T2 = T1 + α (T1 - T0) (Equation 1)

[0032] For example, when the target temperature T1 is 15°C, the room temperature T0 is 25°C, and the temperature coefficient α is 0.5, the control unit controls the refrigerant temperature adjustment device 32 so that the refrigerant temperature T2 becomes 10°C. It is preferable that the control unit controls the refrigerant temperature to be lower (for example, 5°C) than the refrigerant temperature T2 (10°C) calculated by Equation 1 until the target temperature T1 is reached ±2°C. This makes it possible to shorten the time until the temperature of the liquid La reaches the target temperature T1. The control unit may perform feedback control based on the temperature measured by the temperature sensor.

[0033] The liquid temperature adjustment means 3 may include an input unit (not shown) for inputting the target temperature T1, a display unit (not shown) for displaying the target temperature T1, the refrigerant temperature T2, a temperature measured by a temperature sensor, etc., and a calculation unit for calculating the refrigerant temperature T2. The control unit, the input unit, the display unit, and the calculation unit may be provided in a control device 8 (see FIG. 1) described later, or may be provided separately from the control device 8.

[0034] The liquid temperature adjustment means 3 can adjust the liquid Lq to, for example, -20°C to 100°C. When measuring wet μ, the liquid temperature adjustment means 3 only needs to adjust the liquid Lq to 0°C to 40°C. The road surface member 1 can also be adjusted to the same temperature as the liquid Lq. This makes it possible to perform friction tests assuming various environments such as different seasons and overseas.

[0035] As shown in FIG. 1, the friction testing apparatus 100 of this embodiment includes a holder 4 that holds the test rubber body R, a loading device 5 that presses the test rubber body R against the test road surface 1a, a driving device 6 for moving the test rubber body R relative to the test road surface 1a, a load sensor 7 that measures the load acting on the test rubber body R, and a control device 8 that controls the operations required for the test, but is not limited to this.

[0036] The holder 4 is connected to a loading device 5. The loading device 5 is configured to be able to reciprocate the holder 4 in the Z direction (the up and down direction in FIG. 1) perpendicular to the test road surface 1a. By appropriately setting the position of the holder 4 (the distance between the holder 4 and the test road surface 1a), the load in the Z direction input to the test rubber body R can be adjusted, and thus the test rubber body R can be pressed against the test road surface 1a under predetermined pressure conditions. The loading device 5 is configured by a servo motor, but other actuator mechanisms may also be used.

[0037] The driving device 6 is configured to reciprocate a table 9 supporting the load device 5 along the X direction (left-right direction in FIG. 1). The movement of the table 9 moves the holder 4, and the test rubber body R can be moved while sliding on the test road surface 1a. The actuator 10 is configured to reciprocate the table 9 along the Y direction (direction perpendicular to the paper surface of FIG. 1) perpendicular to both the X direction and the Z direction, and is used for aligning the test rubber body R with the test road surface 1a in the Y direction and for changing lanes. In this embodiment, the driving device 6 and the actuator 10 are each configured by a servo motor, but are not limited to this.

[0038] The load sensor 7 can measure three load components in total, a vertical component and two horizontal components, and can measure the load in the Z direction (vertical force), the load in the X direction (front-rear force), and the load in the Y direction (lateral force) acting on the test rubber body R. The load sensor 7 is, for example, configured with a load cell. In this embodiment, the load sensor 7 is attached to the upper side of the holder 4 (the side opposite to the test rubber body R).

[0039] The control device 8 includes a calculation unit 8a that performs calculations required for measuring the friction coefficient, an operation control unit 8b that controls the operation of the load device 5 and the drive device 6, an input unit 8c that receives input from a test operator, and a display unit 8d that displays on a screen various information related to the operation and settings of the friction test device 100. The measurement value by the load sensor 7 is sent to the control device 8, and the calculation unit 8a calculates the friction coefficient based on the measurement value.

[0040] In the friction test device 100, the flat surface of the test rubber body R is pressed against a test road surface 1a simulating an actual road surface, and the load when the test rubber body R is moved linearly while sliding on the flat test road surface 1a is measured, and the friction coefficient between the test road surface 1a and the test rubber body R is measured. Both the static friction coefficient and the dynamic friction coefficient can be measured. In addition, depending on the presence or absence of liquid on the test road surface 1a, the friction coefficient of both a dry road surface and a wet road surface can be measured. The pressure conditions of the test rubber body R pressed against the test road surface 1a, as well as the conditions related to the linear movement such as the speed and the route, are controlled by the control device 8. The moving speed can be set so that the test rubber body R slides at a uniform speed over a predetermined section.

[0041] In this way, by pressing the flat surface of the test rubber body R against the flat test road surface 1a, when the test rubber body R is moved straight while sliding, the change in the contact area is small and stable, and unevenness of the contact pressure can be suppressed. Note that this contact area is not the real contact area with respect to the unevenness of the test road surface 1a, but is the apparent contact area observed when pressed against a flat plate. In addition, in this embodiment, the test rubber body R is moved straight on the test road surface 1a instead of turning, so that the occurrence of speed differences within the contact surface is suppressed. Therefore, according to this device, the friction coefficient between the test road surface 1a and the test rubber body R can be measured with high accuracy.

[0042] The linear movement of the test rubber body R may be any movement of the test rubber body R along the longitudinal direction (X direction) of the test road surface 1a, and examples thereof include the embodiment shown in FIG. 4. In (a), the test rubber body R moves linearly, and the path of movement coincides with the longitudinal direction. In (b) and (c), the test rubber body R is vibrated, and in both cases the test rubber body R moves along the longitudinal direction while vibrating in the Y direction. When observed microscopically, (b) is a movement along a triangular wave, and (c) is a movement along a sine wave, but the center of the width of their vibrations coincides with the longitudinal direction, and such movements are also included in the linear movement.

[0043] In addition to the above-mentioned Y-direction excitation, X-direction excitation and Z-direction excitation can also be applied, which are also included in linear movement. When excitation is applied in the X-direction, the motion is a reciprocating motion along the longitudinal direction, and for example, a triangular wave or sine wave excitation is used. When excitation is applied in the Z-direction, the motion is an up-down motion, and for example, a triangular wave, sine wave, pulse wave, or trapezoidal wave excitation is used.

[0044] It is desirable that the contact area of ​​the test rubber body R does not change between when stationary and when sliding under a given pressure condition. This pressure condition is about 300 to 600 kPa in the case of rubber materials used in passenger car tires, but is higher in truck and bus tires. Even if there is a change in the contact area, the area reduction rate is preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less. In order to suppress the reduction in the contact area, it is effective to devise the shape of the test rubber body R as described later.

[0045] The area reduction rate of the test rubber body R is expressed as (S1-S2) / S1, where S1 is the contact area when stationary and S2 is the contact area when sliding. This area reduction rate can be measured, for example, by attaching a transparent glass plate or prism to a sub-section of the test road surface 1a other than the main section required for measuring the friction coefficient, and photographing the contact surface of the rubber test piece passing over it, and using an image obtained. Alternatively, it can be measured using a pressure measuring device attached to the main section or sub-section.

[0046] FIG. 5 shows a preferred shape of the test rubber body R. (a) is a front view seen from the same direction as FIG. 1, and the right side of this is the front of the sliding direction of the test rubber body R. (b) is a bottom view, and (c) is a right side view. The test rubber body R has a flat surface Rf that is pressed against the test road surface 1a. The side surface Rs of the front edge rises from the flat surface Rf. As in this example, it is preferable that the side surface Rs of the front edge and the flat surface Rf form an obtuse angle. This makes it difficult for the front edge to get caught on the test road surface 1a when the test rubber body R is moved straight while sliding, and suppresses a decrease in the contact area and unevenness in the contact pressure.

[0047] As described above, the angle θ1 is preferably greater than 90 degrees, which can suppress catching of the front edge. From the viewpoint of enhancing this effect, the angle θ1 is preferably greater than or equal to 100 degrees, and more preferably greater than or equal to 120 degrees. Moreover, in order to prevent the side surface Rs of the front edge from contacting the test road surface 1a, the angle θ1 is preferably less than or equal to 170 degrees, and more preferably less than or equal to 150 degrees. The shape of the rear edge is not particularly limited, and although it is formed at a right angle in FIG. 5, it may be the same shape as the front edge.

[0048] When measuring the coefficient of friction (wet μ) on a wet road surface, it is preferable that the height h of the side surface Rs of the front edge of the test rubber body R is greater than the thickness Th of the liquid film (see FIG. 3). This reduces the resistance of the liquid film under high-speed sliding conditions and improves measurement accuracy.

[0049] When the angle θ1 is an obtuse angle, various shapes as shown in FIG. 6 can be adopted for the side surface Rs of the front edge. Of these, in (a) to (c), the side surface Rs is formed by an inclined surface inclined with respect to the flat surface Rf. (a) has the same shape as FIG. 3, and the side surface Rs has a chamfered shape of an angular surface. In (d) and (e), the side surface Rs is formed by a curved surface. The side surface Rs of (d) has a chamfered shape of a rounded surface, and its radius of curvature is set to, for example, 0.5 to 5 mm. The side surface Rs of (e) has a chamfered shape of a spoon surface, and its radius of curvature is set to, for example, 0.5 to 10 mm.

[0050] <Friction test method> Next, an example of a friction test method will be described with reference to FIGS.

[0051] 2 and 3, first, liquid Lq is brought into contact with a road surface member 1 having a test road surface 1a (liquid contacting step), and the temperature of the liquid Lq is adjusted (liquid temperature adjusting step). This makes it possible to adjust the temperature of the road surface member 1 via the liquid Lq. The liquid temperature adjusting step may be performed before the liquid contacting step, after the liquid contacting step, or simultaneously with the liquid contacting step.

[0052] The liquid contact step is preferably carried out in a liquid tank 21 that stores the liquid Lq. The liquid tank 21 is preferably equipped with a heat insulating layer 211 as described above. In the liquid contact step, it is preferable to form a film of the liquid Lq on the test road surface 1a. In the liquid contact step, it is preferable to bring the liquid Lq into contact with each of the side surfaces 1b, 1c of the road surface member 1 located at both ends in the short direction of the test road surface 1a formed into a shape having a longitudinal direction.

[0053] After the temperature of the road surface member 1 reaches near the target temperature (target temperature ±2 degrees, preferably target temperature ±1 degree), the test rubber body R (see FIG. 5) is moved relative to the test road surface 1a to perform a friction test of the test rubber body R (friction test process). Specifically, the flat surface Rf of the test rubber body R is pressed against the test road surface 1a, and the load when the test rubber body R is moved linearly while sliding on the test road surface 1a is measured, and the friction coefficient between the test road surface 1a and the test rubber body R is measured.

[0054] When measuring the coefficient of friction (wet μ) on a wet road surface, with a film of liquid Lq formed on the test road surface 1a, the flat surface Rf of the test rubber body R is pressed against the test road surface 1a, and the load applied when the test rubber body R is moved in a straight line while sliding on the wet test road surface 1a is measured, and the coefficient of friction (wet μ) between the wet test road surface 1a and the test rubber body R is measured.

[0055] It is preferable that the operator supplies the liquid Lq to the liquid tank 21 so that the thickness of the film of the liquid Lq becomes greater than the thickness Th of the film during the test (see FIG. 3). This is because the liquid Lq evaporates before the road surface member 1 reaches the target temperature, and the thickness of the film may become smaller than the thickness Th. This is also because the temperature of the road surface member 1 changes less when the thickness of the film is adjusted by reducing the amount of liquid Lq than when the thickness of the film is adjusted by adding the liquid Lq after the road surface member 1 reaches the target temperature. From the viewpoint of improving the measurement accuracy of the friction coefficient (wet μ), it is preferable to remove air bubbles generated on the test road surface 1a after the film of the liquid Lq is formed (after the liquid Lq is supplied to the liquid tank 21) using a brush or the like. This is because the liquid Lq cannot enter between the unevenness of the test road surface 1a due to surface tension, and these parts become air bubbles.

[0056] After the friction test, the liquid Lq in the liquid tank 21 and rubber residue from the test rubber body R are removed. The liquid Lq is removed from the liquid tank 21, for example, by sucking it out with a vacuum cleaner or by providing a drainage hole or the like in the liquid tank 21. As described above, the liquid Lq is preferably water (tap water, distilled water, etc.) from the viewpoint of facilitating cleaning of the test road surface 1a.

[0057] [1] As described above, the friction test apparatus 100 of this embodiment comprises a road surface member 1 having a test road surface 1a that contacts the test rubber body R, a liquid contact means 2 that brings liquid Lq into contact with the road surface member 1, and a liquid temperature adjustment means 3 that can adjust the temperature of the liquid Lq that contacts the road surface member 1.

[0058] According to this configuration, the temperature of the road surface member 1 can be adjusted via the liquid Lq by bringing the liquid Lq adjusted by the liquid temperature adjustment means 3 into contact with the road surface member 1. This improves heat conduction to (from) the road surface member 1 compared to when temperature is adjusted by a heater, and makes it possible to suppress temperature variations in the road surface member 1.

[0059] [2] In addition, in the friction test device 100 described in [1] above, it is preferable that the liquid contacting means 2 includes a liquid tank 21 that stores the liquid Lq, and the road surface member 1 is accommodated in the liquid tank 21.

[0060] According to this configuration, by storing the road surface member 1 in the liquid tank 21, the liquid Lq can be constantly in contact with the road surface member 1 when adjusting the temperature of the road surface member 1. This makes it easier to adjust the temperature of the road surface member 1, and further reduces variation in the temperature of the road surface member 1.

[0061] [3] In the friction testing device 100 described in [2] above, the liquid tank 21 is preferably provided with a heat insulating layer 211.

[0062] With this configuration, the influence of the room temperature in which the friction test device 100 is installed is reduced, making it easier to regulate the temperature of the liquid Lq stored in the liquid tank 21 compared to when a liquid tank without a thermal insulation layer is used. This also makes it easier to regulate the temperature of the road surface member 1, and makes it possible to further suppress variations in the temperature of the road surface member 1.

[0063] [4] In the friction test device 100 described in any one of the above [1] to [3], the liquid contacting means 2 is preferably configured to be capable of forming a film of the liquid Lq on the test road surface 1a.

[0064] According to this configuration, by bringing the test road surface 1a into contact with the liquid Lq, it becomes easy to adjust the temperature of the test road surface 1a that is in contact with the test rubber body R of the road surface member 1. This makes it possible to suppress variation in the temperature of the test road surface 1a.

[0065] [5] Furthermore, in the friction testing device 100 described in any one of [1] to [4] above, it is preferable that the test road surface 1a is formed into a shape having a longitudinal direction, and the liquid contacting means 2 brings the liquid Lq into contact with each of the side surfaces 1b, 1c of the road surface member 1 located at both ends of the shorter side of the test road surface 1a.

[0066] According to this configuration, by sandwiching the road surface member 1 between the liquid Lq, it becomes easy to adjust the temperature of the road surface member 1. This makes it possible to further suppress the variation in temperature of the road surface member 1.

[0067] [6] The friction testing method of this embodiment includes a liquid contacting process for bringing liquid Lq into contact with a road surface member 1 having a test road surface 1a, a liquid temperature adjusting process for adjusting the temperature of the liquid Lq, and a friction testing process for moving the test rubber body R relative to the test road surface 1a to perform a friction test on the test rubber body R.

[0068] According to this method, the temperature of the road surface member 1 can be adjusted via the liquid Lq by bringing the liquid Lq adjusted in the liquid temperature adjustment process into contact with the road surface member 1. This improves heat conduction to (from) the road surface member 1 compared to when the temperature is adjusted by a heater, and makes it possible to suppress temperature variations in the road surface member 1.

[0069] [7] In the friction test method described in [6] above, the liquid contact step is preferably carried out in a liquid tank 21 that stores the liquid Lq.

[0070] According to this method, by performing the liquid contacting step in the liquid tank 21, it is possible to constantly bring the liquid Lq into contact with the road surface member 1 during temperature adjustment of the road surface member 1. This makes it easier to adjust the temperature of the road surface member 1, and further suppresses temperature variations in the road surface member 1.

[0071] [8] In the friction test method described in [7] above, the liquid tank 21 preferably includes a heat insulating layer 211.

[0072] According to this method, the influence of the room temperature in which the friction test is performed is reduced, and it is easier to regulate the temperature of the liquid Lq stored in the liquid tank 21 compared to when a liquid tank without a thermal insulation layer is used. This makes it easier to regulate the temperature of the road surface member 1, and the variation in the temperature of the road surface member 1 can be further suppressed.

[0073] [9] In the friction testing method according to any one of the above items [6] to [8], the liquid contacting step is preferably a method in which a film of the liquid Lq is formed on the test road surface 1a.

[0074] According to this method, by bringing the test road surface 1a into contact with the liquid Lq, it becomes easy to adjust the temperature of the test road surface 1a that is in contact with the test rubber body R of the road surface member 1. This makes it possible to suppress variation in the temperature of the test road surface 1a.

[0075]

[10] In addition, in the friction testing method described in any one of [6] to [9] above, it is preferable that the liquid contacting step involves bringing liquid Lq into contact with each side 1b, 1c of the road surface member 1 located at both ends in the short direction of the test road surface 1a formed into a shape having a longitudinal direction.

[0076] According to this method, by sandwiching the road surface member 1 between the liquid Lq, it becomes easy to adjust the temperature of the road surface member 1. This makes it possible to further suppress the variation in temperature of the road surface member 1.

[0077] The friction test apparatus 100 and the friction test method are not limited to the configurations of the above-mentioned embodiments, and are not limited to the above-mentioned effects. Of course, the friction test apparatus 100 and the friction test method can be modified in various ways without departing from the gist of the present invention. For example, it is of course possible to arbitrarily select one or more of the configurations, methods, etc. of the various modified examples described below and adopt them in the configurations, methods, etc. of the above-mentioned embodiments.

[0078] (A) In this embodiment, the liquid temperature adjustment means 3 is equipped with a liquid-cooling type liquid temperature adjustment device, but is not limited to this. For example, the liquid temperature adjustment means 3 may be equipped with an air-cooling type liquid temperature adjustment device that can adjust the temperature of the liquid Lq using a fan or the like. Furthermore, the liquid temperature adjustment means 3 may be equipped with a water heater that heats the liquid Lq.

[0079] (B) In this embodiment, the liquid contact means 2 includes a liquid tank 21 that stores the liquid Lq, but is not limited to this. For example, the liquid contact means 2 may include an ejection device that ejects the liquid Lq onto the road surface member 1. The ejection device may constantly eject the liquid Lq toward the road surface member 1, or may eject the liquid Lq intermittently.

[0080] (C) In this embodiment, the liquid temperature adjustment means 3 adjusts the temperature of the liquid Lq stored in the liquid tank 21, but this is not limited to the above. For example, the liquid temperature adjustment means 3 may adjust the temperature of the liquid Lq before it is stored in the liquid tank 21. Specifically, the friction testing device 100 may include a supply means for supplying the liquid Lq to the liquid tank 21, and the liquid temperature adjustment means 3 may adjust the temperature of the liquid Lq supplied by the supply means. In the configuration of (B) above, a supply pipe for supplying the liquid Lq adjusted by the liquid temperature adjustment means 3 is connected to the injection device.

[0081] (D) In ​​this embodiment, the test road surface 1a is provided along the horizontal direction, and the loading device 5 is configured to be able to reciprocate the holder 4 along the Z direction (the up-down direction in FIG. 1) perpendicular to the test road surface 1a, but is not limited to this. For example, the test road surface 1a may be provided along a direction perpendicular to the horizontal direction, and the loading device 5 may be configured to be able to reciprocate the holder 4 along the Y direction perpendicular to the test road surface 1a.

[0082] (E) The friction test apparatus 100 according to the present embodiment measures the load when the test rubber body R is caused to move linearly while sliding, but is not limited to this. For example, the friction test apparatus 100 may measure the load when the test rubber body R is caused to move linearly while rolling. The friction test apparatus 100 may also measure the load when the test rubber body R is caused to move in a rotational manner.

[0083] (F) The friction test device 100 may be equipped with an ambient temperature adjustment device (for example, a thermostatic bath or a thermostatic room) that can adjust the ambient temperature. This makes it easier to adjust the temperature of the road surface member 1, and further reduces variations in the temperature of the road surface member 1. [Explanation of symbols]

[0084] 100... friction test device, 1... road surface member, 1a... test road surface, 2... liquid contact means, 21... liquid tank, 211... heat insulating layer, 211a... groove, 212... rubber body, 3... liquid temperature adjustment means, 31... refrigerant pipe, 32... refrigerant temperature adjustment device, 4... holder, 5... load device, 6... drive device, 7... load sensor, 8... control device, 8a... calculation unit, 8b... operation control unit, 8c... input unit, 8d... display unit, 9... table, 10... actuator, 20... metal plate, R... test rubber body, Rf... flat surface, Rs... side, Lq... liquid

Claims

1. a road surface member having a test road surface that comes into contact with the test rubber body; A liquid contacting means for bringing a liquid into contact with the road surface member; and a liquid temperature adjusting means capable of adjusting the temperature of the liquid in contact with the road surface member.

2. the liquid contact means includes a liquid tank for storing the liquid; The friction testing device according to claim 1 , wherein the road surface member is contained in the liquid tank.

3. 3. The friction testing device of claim 2, wherein the liquid bath includes a thermal insulation layer.

4. 2. The friction testing device according to claim 1, wherein the liquid contacting means is configured to be capable of forming a film of the liquid on the test road surface.

5. The test surface is formed into a shape having a longitudinal direction, 5. The friction testing device according to claim 1, wherein the liquid contacting means brings the liquid into contact with each side of the road surface member located at both ends in the short direction of the test road surface.

6. A liquid contacting step of contacting a liquid with a road surface member having a test road surface; a liquid temperature adjusting step of adjusting the temperature of the liquid; and a friction testing step of moving the test rubber body relative to the test road surface to conduct a friction test on the test rubber body.

7. The friction testing method according to claim 6 , wherein the liquid contacting step is carried out in a liquid tank that stores the liquid.

8. 8. The friction testing method of claim 7, wherein the liquid bath comprises a thermal insulation layer.

9. The friction testing method according to claim 6 , wherein the liquid contacting step comprises forming a film of the liquid on the test road surface.

10. A friction testing method according to any one of claims 6 to 9, wherein in the liquid contacting step, the liquid is brought into contact with each side of the road surface member located at both ends of the short side of the test road surface formed into a shape having a longitudinal direction.

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