Method for collecting tire wear particles

Abstract

The present invention aims to provide a method for recovering tire wear particles that can increase the recovery rate of tire wear particles. [Solution] The present invention provides a method for collecting tire wear particles, comprising: a first collection step of using a suction device to suck up tire wear particles from a suction nozzle located at least one location around the tire house while the vehicle is in motion; a second collection step of collecting objects on the road surface that the vehicle has passed over; and a separation step of separating the wear particles collected in the first collection step and the objects collected in the second collection step into tire wear particles and other materials.

Description

Technical Field

[0001] The present invention relates to a method for recovering tire wear powder.

Background Art

[0002] When a vehicle equipped with tires travels on a road surface, tire wear powder is generated due to the friction between the tires and the road surface. Conventionally, a method for recovering tire wear powder has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, with the method described in Patent Document 1, it has been difficult to recover a sufficient amount of tire wear powder.

[0005] Therefore, an object of the present invention is to provide a method for recovering tire wear powder that can increase the recovery rate of tire wear powder.

Means for Solving the Problems

[0006] The gist configuration of the present invention is as follows. (1) A first recovery step of sucking the wear powder in the tire house by a suction machine that sucks tire wear powder from a suction nozzle disposed at at least one location around the tire housed in the tire house while the vehicle is running; A second recovery step of recovering the powder on the road surface through which the vehicle has traveled; A method for recovering tire wear particles, comprising a separation step of separating the wear particles recovered in the first recovery step and the objects recovered in the second recovery step into tire wear particles and other materials. In this specification, "rear" means the direction opposite to the direction of travel of a vehicle, when the direction of travel is considered to be forward.

[0007] (2) The tire wear dust collection method according to (1) above, wherein the entire wheel well is covered with a film.

[0008] (3) The tire wear dust collection method according to (1) or (2), wherein the suction nozzle is provided for both the front and rear wheels on at least the same side, either left or right.

[0009] (4) A method for collecting tire wear particles according to any one of (1) to (3) above, wherein the vehicle speed is between 10 km / h and 60 km / h.

[0010] (5) The method of collecting tire wear dust according to any one of (1) to (4) above, wherein the vehicle is driven in a circular motion.

[0011] (6) A method for collecting tire wear dust according to any one of (1) to (5) above, wherein the wind speed when the vehicle is running is 10 m / s or less.

[0012] (7) A method for collecting tire wear particles according to any one of (1) to (6) above, wherein the temperature of the vehicle during operation is -20 to 40°C, the humidity is 50 to 90%, and the road surface temperature is -20 to 70°C.

[0013] (8) The tire wear powder recovery method according to any one of (1) to (7), wherein the separation step is performed in a solvent.

[0014] (9) The tire wear powder recovery method according to any one of (1) to (7), wherein the separation step is performed by sieving according to particle size.

[0015] (10) Of the films, the outer film covering the outside of the tire house consists of an upper part having a bending strength with a Clark stiffness of 400 or more and a lower part having a Clark stiffness lower than that of the upper part. The tire wear powder recovery method according to any one of (1) to (9) above, wherein the upper part is fixed to a fixing member connected to a connecting member attached to the vehicle body. Here, the bending strength of the "film" refers to the Clark stiffness measured according to JIS P 8143. Also, in this specification, the bending strength of the "frame" shall refer to the bending strength measured according to JIS Z 2204.

[0016] (11) The tire wear powder recovery method according to any one of (1) to (10) above, wherein the vehicle travels in autonomous driving.

[0017] (12) The tire wear powder recovery method according to any one of (1) to (11) above, wherein the vehicle is an electric vehicle.

Effect of the Invention

[0018] According to the present invention, it is possible to provide a tire wear powder recovery method capable of increasing the recovery rate of tire wear powder.

Brief Description of the Drawings

[0019] [Figure 1] It is a view of the vehicle body seen from the side for explaining a tire wear powder recovery system that can be used in the tire wear powder recovery method according to an embodiment of the present invention. [Figure 2] It is a view of the vehicle body seen from the back for explaining a tire wear powder recovery system that can be used in the tire wear powder recovery method according to an embodiment of the present invention. [Figure 3] It is a view of the vehicle body seen from the side with the tire removed for explaining a tire wear powder recovery system that can be used in the tire wear powder recovery method according to an embodiment of the present invention. [Figure 4]This is a view of the vehicle body seen from the bottom side for explaining a tire wear powder recovery system that can be used in a tire wear powder recovery method according to an embodiment of the present invention.

Embodiment for Carrying out the Invention

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0021] <Tire Wear Powder Recovery System> For the sake of convenience, an example of a tire wear powder recovery system that can be used in a tire wear powder recovery method according to an embodiment of the present invention will be described first. FIG. 1 is a side view of the vehicle body for explaining a tire wear powder recovery system that can be used in a tire wear powder recovery method according to an embodiment of the present invention. FIG. 2 is a rear view of the vehicle body for explaining a tire wear powder recovery system that can be used in a tire wear powder recovery method according to an embodiment of the present invention. FIG. 3 is a side view of the vehicle body with the tire removed for explaining a tire wear powder recovery system that can be used in a tire wear powder recovery method according to an embodiment of the present invention. FIG. 4 is a view of the vehicle body seen from the bottom side for explaining a tire wear powder recovery system that can be used in a tire wear powder recovery method according to an embodiment of the present invention.

[0022] The vehicle body 2 to which the tire wear powder recovery system (hereinafter, also simply referred to as "system") 1 is applied can be various types for recovering tire wear powder of various tires T, but from the viewpoint of ensuring reproducibility, it is preferably the vehicle body of an autonomous vehicle. Also, from the viewpoint of suppressing the discharge of powders other than the wear powder, it is preferably the vehicle body of an electric vehicle.

[0023] As shown in Figure 3, in this example, the vehicle body 2 is equipped with a drive shaft 21, a front spring damper 22, a steering tie rod 23, and a lower arm 24 at the front wheel section. The vehicle body 2 is also equipped with a lower arm 24, a trailing arm 25, and a shock absorber 26 at the rear wheel section.

[0024] A tire T is housed in the wheel well 3 of the vehicle body 2, and the tire T is attached to the vehicle body 2. The tire T to which this system 1 is applied can also be of various types in order to collect various tire wear particles.

[0025] As shown in Figures 1 to 4, this system 1 includes a film 4 that covers the entire wheel well 3. In this example, the film 4 covers the outside (see Figures 1 and 2), inside (see Figure 3), rear (see Figure 2), front (same configuration as the rear in Figure 2), and interior of the wheel well 3, and the inside of the wheel well 3 is surrounded by these and the road surface.

[0026] The outer film 4 covering the outside of the wheel well 3 will be described in detail. The outer film 4 is fixed to a fixing member 6 connected to a connecting member 5 attached to the vehicle body 2. Specifically, as shown in Figures 1 and 2, the outer film 4 is fixed to a fixing member (frame) 6 connected to a connecting member 5 attached to the vehicle body 2. The bending strength of the frame 6 is 90 MPa or more. This allows the outer film 4 to be stably fixed. On the other hand, if the vehicle body 2 has a fender that partitions the wheel well 3, the outer film 4 covering the outside of the wheel well 3 may be fixed to the fender, which is a fixing member. In this case, system 1 does not need to have a connecting member 5 and a frame 6.

[0027] In this example, the connecting member 5 includes an attachment portion for attaching to the vehicle body 2 and a fixing portion for fixing the frame 6. The attachment portion is not particularly limited as long as it can be attached to the vehicle body 2. The fixing portion can be a gripping portion capable of gripping and fixing the (partially) rod-shaped frame 6. The connecting member 5 can also be molded using a 3D printer so that the fixing portion, which is the gripping portion, can grip frames 6 that correspond to various vehicle (size) configurations. Although not particularly limited, the connecting member 5 can be made of resin to reduce the weight of the component.

[0028] The frame 6 can have a rectangular (side) shape when viewed from the side, as shown in the figure. That is, in this example, the frame 6 has two rod-shaped parts extending in the front-rear direction of the vehicle body 2 and two rod-shaped parts extending in the vertical direction. The ends of the two rod-shaped parts extending in the front-rear direction of the vehicle body 2 are connected to the two rod-shaped parts extending in the vertical direction. In the illustrated example, two such rectangular (side) frames are connected vertically (one side is shared). Furthermore, the frame 6 is not limited to the above shape, as it only needs to have a shape suitable for stably fixing the outer film 4. The bending strength of the frame 6 is preferably 90 MPa or more in order to stably fix the film 4. The upper limit of the bending strength of the frame 6 is not particularly limited. The material of the frame 6 is not particularly limited, but a metal frame can be given as an example.

[0029] The distance between the outer film 4 and the vehicle body 2 is preferably between 1 cm and 10 cm. By setting the distance to 1 cm or more, sufficient distance from the tire T can be ensured to prevent contact between the tire T and the film 4. On the other hand, by setting the distance to 10 cm or less, the volume of the wheel well 3 is reduced, thereby increasing the suction effect and allowing for efficient collection of tire wear particles. For similar reasons, it is more preferable that the distance between the outer film 4 and the vehicle body 2 is between 2 cm and 8 cm.

[0030] In this example, the outer film 4 has portions with different bending strengths in the vertical direction. Specifically, the outer film 4 has a first portion 4a with high bending strength and a second portion 4b with lower bending strength than the first portion 4a. In this example, the first portion 4a is the upper portion located at the top in the vertical direction, and the second portion 4b is the lower portion located at the bottom in the vertical direction.

[0031] In this example, the upper portion 4a has a bending strength such that its Clark stiffness is 400 or more. That is, the outer film 4 consists of an upper portion 4a having a bending strength such that its Clark stiffness is 400 or more, and a lower portion 4b having a Clark stiffness lower than that of the upper portion 4a. As a result, the upper portion 4a is stably fixed, while the lower portion 4b, which is partially in contact with the road surface, has low bending strength, thus suppressing the generation of powder when it comes into contact with the road surface. Furthermore, from the viewpoint of suppressing the generation of powder when it comes into contact with the road surface, the bending strength of the lower portion 4b is not particularly limited, but it is preferable that its Clark stiffness is 200 or less. On the other hand, from the viewpoint of maintaining functionality against wind associated with driving, it is preferable that the bending strength of the lower portion 4b has a Clark stiffness of 30 or more.

[0032] In this example, the upper part 4a is fixed to the frame 6 or the fender.

[0033] In this example, the upper portion 4a is positioned 3 cm to 10 cm above the road surface (the shortest vertical distance between the upper portion 4a and the road surface is 3 cm to 10 cm), and at least a portion of the lower portion 4b can contact the road surface. It is more preferable that the entire lower portion 4b can contact the road surface.

[0034] The specific gravity of the lower portion 4b is preferably 1 or less. This makes it easier to separate the tire wear particles from the wear particles collected later, due to the difference in specific gravity, and to collect only the tire wear particles. It also makes it possible to reduce the weight of system 1.

[0035] Such films with different bending strengths can be manufactured using the multi-component copolymer described in International Publication No. 2017 / 065298. By adjusting the blending ratio and arrangement of each component, the bending strength can be adjusted, and the lower portion 4b that contacts the road surface can be made highly wear-resistant, thereby suppressing the generation of wear particles other than those from the tire. Furthermore, while films with different bending strengths can be made from two or more films, they can also be formed continuously using such a multi-component copolymer.

[0036] The first portion 4a is preferably made of a conductive film. This is because it makes it easier to collect tire wear particles adhering to the first portion 4a. More specifically, the surface resistance of the first portion 4a is 1.0 × 10⁻⁶. 8 It is preferable that the impedance is Ω or less. The material of the second portion 4b is not particularly limited, but polyethylene terephthalate is an example.

[0037] Referring to Figure 3, the inner film 4 covering the inside of the wheel well 3 also has parts with different bending strengths in the vertical direction. Specifically, the inner film 4 has a first part 4a with high bending strength and a second part 4b with lower bending strength than the first part 4a. In the front wheel section, the parts are arranged in the order of first part 4a, second part 4b, first part 4a, and second part 4b from top to bottom. In the rear wheel section, the parts are also arranged in the order of first part 4a, second part 4b, first part 4a, and second part 4b from top to bottom. The second part 4b of the inner film 4 has a bending strength of 80 MPa or less. Thus, in this example, the inner film 4 covering the inside of the wheel well 3 has a part (second part 4b) with a bending strength of 80 MPa or less. In the front and rear wheel sections, the part that contacts the road surface (lowest part) is made of the second part 4b, which suppresses the generation of powder due to friction with the road surface. Furthermore, in the front wheel section, the second portion 4b (with low bending strength) is also applied near the drive shaft 21 and steering tie rod 23, which move in response to steering (the second upward-convex portion from the top). In the rear wheel section, the second portion 4b (with low bending strength) is also applied to the region where the suspension vibrates (the second portion from the top). The low bending strength of the second portion 4b allows it to follow the movement of the components of the vehicle body 2. In the illustrated example, the lower first portion 4a and the second portion 4b are fixed to the lower arm 24.

[0038] The portion (4a) of the inner film 4 that is different from the aforementioned portion (4b) is preferably a conductive film, and its surface resistance value is 1.0 × 10 8 It is preferable that the impedance is Ω or less, because it makes it easier to collect tire wear particles adhering to the first portion 4a. In the inner film 4, the material of the second portion 4b is not particularly limited, but polyethylene terephthalate can be used as an example.

[0039] As shown in Figures 2 and 4, the rear film 4 covering the rear side of the wheel well 3 also has portions 4a and 4b with different bending strengths in the vertical direction. In the illustrated example, the upper portion 4a, located at the top when viewed from the rear, has a roughly L-shape, and the lower portion 4b, located at the bottom, has a rectangular shape. On the other hand, the shape of the rear film 4 can also be varied. Although not shown in the illustration, the front film covering the front side of the wheel well 3 also has portions with different bending strengths in the vertical direction. For example, similar to the rear side, the upper portion 4a, located at the top, can have a roughly L-shape, and the lower portion 4b, located at the bottom, can have a rectangular shape, but this example is not limited to this. The material and bending strength of these portions 4a and 4b can be the same as those of the first portion 4a and second portion 4b of the outer film and inner film, respectively.

[0040] Furthermore, although not shown in the illustration, the portion of the vehicle body 2 that partitions the wheel well 3 (the portion of the vehicle body 2 that partitions the top of the curved wheel well 3 in a side view) is often protected with felt, for example, and tire wear particles can get trapped inside and become difficult to collect. Therefore, it is preferable to provide an internal film 4 in this portion as well. Thus, in this example, the inside of the wheel well 3 is surrounded by the outer film, inner film, rear film, front film, and internal film, and the road surface. On the other hand, in this disclosure, the shape of the film can be varied, and for example, the inside of the wheel well 3 can be surrounded by a cylindrical film and the road surface.

[0041] Here, as shown in Figures 1 to 4, the system 1 comprises a suction machine 8 for sucking up tire wear particles and a suction nozzle 7 positioned at least at one location around the tire T housed in the wheel well 3. The suction machine 8 and the suction nozzle 7 are connected by a connecting hose 9. The suction machine 8 is not particularly limited as long as it is capable of sucking up tire wear particles, and can be made up of any known suction machine. In this example, the suction machine 8 is housed in the trunk of the vehicle body 2, and therefore the connecting hose extends from the rear of the tire T (where the suction nozzle 7 is located) to the trunk (where the suction machine 8 is housed). Since tire wear particles tend to scatter behind the tire T, it is more preferable that the suction nozzle 7 be positioned at least behind the tire T, as shown in the figure, in order to increase the recovery rate of tire wear particles. The suction nozzle 7 can also be positioned to the side or in front of the tire T, or the suction nozzle 7 can be positioned in two or more locations, for example, behind and to the side of the tire T.

[0042] When the suction device 8 is in operation, the air pressure inside the wheel well 3 becomes lower than atmospheric pressure. This allows for the efficient collection of tire wear particles. To lower the air pressure inside the wheel well 3 below atmospheric pressure, the suction force of the suction device 8 should be increased.

[0043] In this example, System 1 is applied to all four wheels, but it can also be applied to either the left or right front and rear wheels, or to only one of them.

[0044] Although not shown in the illustration, this system 1 is further equipped with a cleaning device for collecting objects on the road surface as the vehicle passes over them. The cleaning device may be a brush, a suction device (separate from the suction device 8), or a combination of these.

[0045] <Method for collecting tire wear particles> A tire wear debris collection method according to one embodiment of the present invention can be carried out, for example, using the system 1 described above. The method of this embodiment includes: a first collection step of using a suction device 8 to suck up tire wear debris from the tire house 3 using a suction nozzle 7 located at least one location around the tire T housed in the tire house 3 (in this example, behind the tire T) while the vehicle is in motion; a second collection step of collecting objects on the road surface that the vehicle has passed over; and a separation step of separating the wear debris collected in the first collection step and the objects collected in the second collection step into tire wear debris and other materials. The tire wear debris collection method of this embodiment will be described below.

[0046] While a vehicle is in motion, wear particles are generated due to rotational friction between the tire T and the road surface. In contrast, the tire wear particle recovery method of this embodiment includes a first recovery step, which involves sucking up the tire wear particles from a suction nozzle 7 located at least one point around the tire T (in this example, behind the tire T) to recover the wear particles generated in the wheel well 3 while the vehicle is in motion. These wear particles may include not only tire wear particles but also wear particles from the road surface. On the other hand, wear particles that cannot be recovered by the first recovery step alone fall onto the road surface. In contrast, the tire wear particle recovery method of this embodiment includes a second recovery step, which allows for the recovery of tire wear particles contained in objects on the road surface. These objects on the road surface may include not only tire wear particles but also larger particles such as fallen leaves and gravel, as well as smaller particles such as wear particles from the road surface and other dust. In this way, the first and second recovery steps allow for the recovery of wear particles and objects that may contain tire wear particles as completely as possible, thereby increasing the recovery rate. Furthermore, since the tire wear debris recovery method of this embodiment includes a separation step, tire wear debris can be separated from these wear debris and other objects (recovered materials). The tire wear debris obtained in this way may be subject to analysis or other treatments. As described above, the tire wear particle recovery method of this embodiment can increase the recovery rate of tire wear particles. Furthermore, since tire wear particles tend to scatter behind the tire T, positioning the suction nozzle 7 at least behind the tire T can increase the recovery rate of tire wear particles.

[0047] Fine tire wear particles may be scattered into the surrounding air by the airflow while driving and by the surrounding wind before reaching the suction nozzle 7. In this method, it is preferable that the entire tire well 3 is covered with the film 4. This is because it suppresses the scattering of tire wear particles and allows for more complete collection of the tire wear particles.

[0048] In this method, it is preferable that the suction nozzle 7 is provided for both the front and rear wheels on at least the same side, either left or right.

[0049] In this method, the vehicle speed is preferably between 10 km / h and 60 km / h.

[0050] In this method, it is preferable that the vehicle is driven in a circular motion. This is because the load conditions applied to the tires (slip angle, camber angle, load, and speed, etc.) can be kept constant during the test, making it easier to understand the relationship with wear.

[0051] In this method, it is preferable that the wind speed while the vehicle is in motion is 10 m / s or less. That is, it is preferable to perform the first recovery step of this method while the vehicle is in motion in an environment where the wind speed when the vehicle is stationary is 10 m / s or less. This is because performing the procedure in an environment where tire wear particles that have fallen onto the road surface are not scattered as much as possible can further increase the recovery rate of tire wear particles.

[0052] In this method, it is preferable that the vehicle temperature during operation is -20 to 40°C, the humidity is 50 to 90%, and the road surface temperature is -20 to 70°C.

[0053] In this method, the separation step is preferably carried out in a solvent. This is because separation can be performed, for example, by utilizing differences in specific gravity. In this case, it is preferable to use a solution with a specific gravity of 0.8 or more and 1.5 or less (e.g., water) to perform separation of the recovered material by specific gravity. This allows for the separation of the recovered material by using the specific gravity of the above solution as a reference, with substances with lower specific gravity floating and substances with lower specific gravity settling. It is also preferable to use a solution with a specific gravity greater than 1.5 to perform separation of the recovered material by specific gravity. This allows for the separation of the recovered material by using the specific gravity of the above solution as a reference.

[0054] Alternatively, in this method, the separation step may be carried out by sieving based on particle size. The sieving is not particularly limited, but a standard particle size can be set between 0.1 and 1 mm, and sieving can be performed accordingly. In addition to separation by suspension and precipitation using a solution, separation based on differences in specific gravity can also be performed by centrifugation. Centrifugation may be performed using a solution to separate the recovered material in the solution, or it may be performed by separating the recovered material in the air using centrifugal force.

[0055] For example, the separation step may involve sieving by particle size, followed by separation of the recovered material by specific gravity using a solution with a specific gravity of 0.8 to 1.5 (e.g., water), and then further separation of the recovered material by specific gravity using a solution with a specific gravity greater than 1.5 (e.g., sodium bromide solution, sodium tungstate solution, etc.). The separation using solutions may be further divided into multiple stages. The separation step using a solution with a specific gravity of 0.8 to 1.5 can be divided into two or more steps using solutions with different specific gravities. Similarly, the separation step using a solution with a specific gravity greater than 1.5 can also be divided into two or more steps using solutions with different specific gravities. In either case, it is preferable to perform the separation using the solution with the higher specific gravity later in the process.

[0056] In this method, the outer film 4 preferably consists of an upper portion 4a having a bending strength of Clark stiffness of 400 or more and a lower portion 4b having a Clark stiffness lower than that of the upper portion 4a, and the upper portion 4a is preferably fixed to a fixing member 6 connected to a connecting member 5 attached to the vehicle body 2. This is because the upper portion 4a is stably fixed, while the lower portion 4b, which is partially in contact with the road surface, has low bending strength, thus suppressing the generation of powder when it comes into contact with the road surface.

[0057] In this method, it is preferable that the vehicle is driven autonomously, as this improves reproducibility. Furthermore, it is preferable that the vehicle be an electric vehicle, as this suppresses the discharge of powders other than wear particles.

[0058] [Contribution to the United Nations-led Sustainable Development Goals (SDGs)] The SDGs have been proposed to realize a sustainable society. One embodiment of this invention is considered to be a technology that can contribute to "No. 12: Responsible Consumption and Production," among others. [Explanation of Symbols]

[0059] 1: Tire wear debris collection system, 2: Vehicle body, 21: Drive shaft, 22: Front spring damper, 23: Steering tie rod, 24: Lower arm, 25: Trailing arm, 26: Shock absorber, 3: Wheel well, 4: Film, 4a: Part 1, 4b: Part 2, 5: Connecting member, 6: Fixing member (frame), 7: Suction nozzle, 8: Suction machine, 9: Connecting hose, T: Tire

Claims

1. A first recovery step involves using a suction device to suck up tire wear particles from the wheel well while the vehicle is in motion, using a suction device that sucks up tire wear particles from at least one suction nozzle located around the tire housed in the wheel well. A second recovery step involves collecting objects on the road surface that the vehicle has passed over, A method for recovering tire wear particles, comprising a separation step of separating the wear particles recovered in the first recovery step and the objects recovered in the second recovery step into tire wear particles and other materials.

2. The method for collecting tire wear particles according to claim 1, wherein the entire wheel well is covered with a film.

3. The tire wear dust collection method according to claim 1 or 2, wherein the suction nozzle is provided for both the front and rear wheels on at least the same side, either left or right.

4. The tire wear dust collection method according to claim 1 or 2, wherein the vehicle travel speed is 10 km / h to 60 km / h.

5. The method for collecting tire wear particles according to claim 1 or 2, wherein the vehicle is driven in a circular motion.

6. The tire wear dust collection method according to claim 1 or 2, wherein the wind speed during vehicle operation is 10 m / s or less.

7. The method for collecting tire wear particles according to claim 1 or 2, wherein the temperature of the vehicle during operation is -20 to 40°C, the humidity is 50 to 90%, and the road surface temperature is -20 to 70°C.

8. The tire wear powder recovery method according to claim 1 or 2, wherein the separation step is performed in a solvent.

9. The tire wear powder recovery method according to claim 1 or 2, wherein the separation step is performed by sieving according to particle size.

10. The outer film of the aforementioned film, which covers the outside of the wheel well, consists of an upper portion having a Clark stiffness of 400 or more and a lower portion having a Clark stiffness lower than that of the upper portion. The tire wear powder collection method according to claim 1 or 2, wherein the upper portion is fixed to a fixing member connected to a connecting member attached to the vehicle body.

11. The tire wear powder collection method according to claim 1 or 2, wherein the vehicle is driven automatically.

12. The tire wear powder collection method according to claim 1 or 2, wherein the vehicle is an electric vehicle.

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