JP7715656B2 - Tire Polishing Equipment - Google Patents

Description

The present invention relates to a tire grinding device.

Conventionally, tire grinding devices have been known that grind tire surfaces by pressing a grinding member such as a grinding belt against the tire surface while rotating the tire (see Patent Documents 1 to 4, etc.). As described in Patent Documents 1 to 3, tire grinding devices are used, for example, to grind and activate the surface of studless tires and restore their grip performance.

Patent Document 1 discloses a device that allows a user to move a grinding device including a grinding belt in the axial direction of a tire by operating a handle mechanism. Patent Document 2 discloses a method that uses a displacement sensor to detect the shape of a tire and calculates the movement trajectory of a grinding member from the detected shape. Furthermore, Patent Document 3 discloses a device that grinds the tire surface by automatically moving a grinding member.

The device described in Patent Document 4 is used to wear down the tires used in the test to match actual driving conditions before conducting a vehicle's actual driving test. Patent Document 4 discloses that the movement of the grinding member is controlled by a control means, and grinding is performed automatically while reading the shape of the tire surface using a non-contact terminal such as a laser.

Japanese Patent Application Laid-Open No. 2007-196347 Japanese Patent Application Laid-Open No. 2004-9484 JP 2012-135829 A Japanese Patent Application Publication No. 9-132013

There is a demand for a tire grinding device that can accurately measure the amount of grinding of a tire and adjust the amount of grinding to a desired value with high precision. However, accurately measuring the amount of grinding is not easy. As a result of the inventors' investigations, they found that the heat generated when grinding a tire causes the tire to expand, and that this thermal expansion is one of the factors that prevents accurate measurement of the amount of grinding.

The object of the present invention is to provide a tire grinding device that can accurately measure the amount of tire grinding.

The tire grinding device of the present invention comprises a drive device that rotates the tire, a grinding device that grinds the tire surface, and a measuring device that measures the amount of tire grinding by irradiating the tire surface with laser light and detecting the light reflected from the tire surface to measure the distance. The measuring device is configured to irradiate the tire's contact patch and groove bottom with the laser light, respectively, and measure the amount of tire grinding from the difference between the measurements at the contact patch and the groove bottom.

The tire grinding device of the present invention makes it possible to accurately measure the amount of tire grinding. Based on the accurate grinding amount measurement results, highly accurate grinding can be achieved.

1 is a plan view schematically illustrating a tire grinding device according to an embodiment; 1 is a block diagram showing a schematic configuration of a tire grinding device. FIG. FIG. FIG. 2 is a diagram showing measurement points for the amount of tire grinding. FIG. 1 is a diagram showing a device for measuring the amount of grinding of a tire. 1 is a flowchart illustrating an example of a control procedure in a tire grinding process. FIG. 10 is a diagram showing an example of a polishing pattern. FIG. 10 is a diagram showing another example of a polishing pattern.

An example of an embodiment of a tire grinding device according to the present invention will be described in detail below with reference to the drawings. The embodiment described below is merely an example, and the present invention is not limited to the following embodiment. Furthermore, the present invention also includes configurations that selectively combine the components of the multiple embodiments and variations described below.

Figure 1 is a plan view of a tire grinding device 10, which is an example of an embodiment, and Figure 2 is a block diagram showing the general configuration of the tire grinding device 10. Note that the grinding device 20 is not shown in Figure 1.

As shown in Figures 1 and 2, the tire grinding apparatus 10 includes a drive device 15 that rotates the tire 1 and a grinding device 20 that grinds the surface of the tire 1. The grinding device 20 is configured to grind the tire surface while moving in the tire axial direction. The grinding device 20 has a grinding belt 21 (see Figure 3, etc., described below) that contacts the tire surface as a grinding member. The tire grinding apparatus 10 grinds the tire surface by pressing the grinding belt 21 against the tire surface while rotating the tire 1.

The tire 1 to be polished by the tire polishing device 10 is not particularly limited, as long as it can be attached to the device. The tire 1 may be, for example, a summer tire, a winter tire (studless tire), or an all-season tire. Furthermore, the tire 1 is not limited to a passenger vehicle tire, but may also be a motorcycle tire, a heavy-duty tire, or the like. The tire 1 has a tread 2 formed with multiple blocks 3 and grooves 5. The blocks 3 are defined by the multiple grooves 5 and protrude in the radial direction of the tire, and are commonly referred to as land. The contact surfaces 4 of the blocks 3 that come into contact with the road surface during use are polished by the polishing belt 21.

The tire polishing device 10 is used, for example, to evaluate the performance of the tire 1. The tire polishing device 10 can accurately and easily achieve the desired level of wear, making it suitable for evaluating performance in various wear states. The tire polishing device 10 may also be used to activate and finish the tire 1.

The tire grinding apparatus 10 includes a base 11 that supports the drive unit 15, grinding device 20, etc. The base 11 may have casters. The base 11 is provided with a tire support shaft 12 that rotatably supports the tire 1 and is rotated by the drive unit 15. The tire 1 is attached to the tire support shaft 12, for example, while mounted on a wheel. In other words, the wheel is attached to the tire support shaft 12. The tire support shaft 12 is installed on the base 11 via a bearing.

The tire grinding apparatus 10 further includes a measuring device 30 for measuring the amount of grinding of the tire 1. The measuring device 30 measures the amount of grinding of the tire by irradiating the tire surface with laser light and detecting the light reflected from the tire surface to measure the distance. As will be described in more detail below, the tire grinding apparatus 10 is configured to use the measuring device 30 to irradiate the contact patch 4 and groove bottom 6 of the tire 1 with laser light, and measure the amount of grinding of the tire from the difference in the measurements at the contact patch 4 and groove bottom 6. In this case, it is possible to accurately measure the amount of grinding even if the tire 1 thermally expands due to grinding.

The tire grinding apparatus 10 includes a movement mechanism 40 that moves the grinding apparatus 20 and a controller 50 that controls the entire apparatus. The movement mechanism 40 has multiple links and multiple cylinders (a first cylinder 46 and a second cylinder 47). The controller 50 controls the operation of the grinding apparatus 20 and the movement mechanism 40, for example, and grinds the tire 1 based on a preset grinding pattern. The tire grinding apparatus 10 also includes a blower 34 for blowing away rubber debris generated by grinding the tire 1. The blower 34 includes a blower body and an air nozzle extending from the blower body.

In this embodiment, the tire 1 is attached to the device with its rotation axis aligned horizontally. The movement mechanism 40 is configured to move the grinding device 20 in the X and Y directions, which are aligned horizontally. In this specification, the "X direction" refers to the direction along the tire axial direction, and the "Y direction" refers to the direction perpendicular to the X direction (tire radial direction) and aligned horizontally. The grinding belt 21 grinds the tire surface while moving in the tire axial direction in contact with the tire surface, thanks to the function of the movement mechanism 40.

As shown in FIG. 2, the driving device 15, grinding device 20, measuring device 30, and moving mechanism 40 are connected to a controller 50. The controller 50 can be a computer installed with software (programs) for executing a series of tire grinding processes. The tire grinding device 10 also includes an encoder 60. As will be described in more detail below, the measuring device 30 irradiates laser light onto measurement points G1 and G2 for the amount of tire grinding based on information acquired by the encoder 60. The encoder 60 may be any device capable of measuring the rotation angle of the tire 1, and there are no particular limitations on the detection method, etc.

The driving device 15 includes, for example, a motor 16 and a transmission mechanism that transmits the rotation of the motor 16 to the tire support shaft 12. Gears, chains, belts, etc. may be used as the transmission mechanism. The encoder 60 may also be connected to the tire support shaft 12. The tire 1 attached to the tire support shaft 12 rotates when the motor 16 is driven. The driving of the motor 16 is controlled by a controller 50. To prevent the tire 1 from falling off the tire support shaft 12 during grinding, the tire 1 is fixed to the tire support shaft 12 by a detachable structure (not shown). Details of the grinding device 20, measuring device 30, and moving mechanism 40 will be described later.

The controller 50 has, for example, a memory that stores various setting information, including the polishing pattern, a control program, etc., and a processor that reads the control program and executes polishing based on the polishing pattern specified by the user. The controller 50 acquires information from each device and sends control commands to each device to execute a series of polishing processes. The controller 50 may be composed of multiple computers, or may include a server or the like connected via a wide area communication network.

The controller 50 includes, for example, a first computer installed on the stand 11 and a second computer connected to the first computer. The first computer may have a touch panel. The touch panel is used as an input interface operated by the user and as a monitor on which various information is displayed. The second computer may be a device dedicated to the tire grinding device 10, or may be a device shared with other systems. Setting information for the grinding pattern may be stored in the memory of the second computer and transmitted from the second computer to the first computer when the grinding process is performed.

In this embodiment, the measurement device 30 is integrated with an air nozzle that constitutes the blower 34. The blower 34 blows air toward measurement points G1 and G2, thereby removing rubber debris adhering to measurement points G1 and G2. The blower 34 is, for example, a blower capable of supplying compressed air capable of blowing away rubber debris. As will be described in more detail below, the blower 34 preferably includes a first outlet for blowing air toward the tire surface, and also a second outlet for blowing air toward the laser light emission port of the measurement device 30.

The configuration of the polishing apparatus 20 and the moving mechanism 40 will be described in detail below, with reference to Figures 1 and 2 as well as Figures 3 and 4 as appropriate. Figures 3 and 4 show the polishing apparatus 20 and a portion of the moving mechanism 40.

As shown in Figures 3 and 4, the polishing device 20 has a polishing belt 21, two pulleys around which the polishing belt 21 is stretched, a motor 26 for rotating the polishing belt 21, and a support frame 27 that supports the motor 26 and other components. The polishing belt 21 is, for example, an endless belt with abrasive grains coated on its surface, and is stretched between a drive pulley 22 and a driven pulley 23. The drive pulley 22 is rotatably fixed to the support frame 27 and rotates using the power of the motor 26. A spring 24 fixed to the support frame 27 is provided between the drive pulley 22 and the driven pulley 23. The driven pulley 23 is biased by the spring 24 in a direction away from the drive pulley 22, thereby maintaining tension on the polishing belt 21.

As will be described in more detail below, the polishing device 20 is configured to polish the tire surface while moving in the tire axial direction based on a preset polishing pattern. Furthermore, the tire surface is polished while the tire 1 is rotated. The user can set multiple polishing patterns, for example, depending on the type of tire 1, evaluation items, etc. Alternatively, the user can select from preset polishing patterns and, after selecting a pattern, input the parameters required for polishing. Information on multiple polishing patterns may be stored in the memory of the controller 50. The polishing device 20 polishes the tire surface while moving from the axially inner to the axially outer side on both axial sides of the tread 2. In this case, the desired polishing level can be achieved with high precision, and the entire desired polishing area can be polished cleanly and evenly.

The sanding belt 21 is positioned opposite the tread 2 and extends vertically. A compression spring is used for the spring 24. The drive pulley 22 and driven pulley 23 are positioned at a vertical distance from each other, and the reaction force of the spring 24 presses the driven pulley 23 in the opposite direction to the drive pulley 22, thereby maintaining the tension of the sanding belt 21. In this embodiment, the reaction force of the spring 24 is applied to the bearing of the driven pulley 23. The sanding device 20 is provided with a lever 25 that is used when replacing the sanding belt 21. When the lever 25 is lifted, the spring 24 is compressed, the driven pulley 23 lowers, and the sanding belt 21 loosens, allowing the belt to be replaced.

The abrasive belt 21 is pressed against the surface of the tread 2 by the function of the movement mechanism 40. In this embodiment, the abrasive pressure when abrading the tire 1 can be adjusted by changing the pressing force applied by the movement mechanism 40.

The abrasive belt 21 rotates in conjunction with the rotation of the drive pulley 22. The drive pulley 22 is rotated by a motor 26, and the rotation direction and speed of the abrasive belt 21 can be adjusted by controlling the motor 26. It is preferable that the abrasive belt 21 rotates in the opposite direction to the rotation direction of the tire 1 at the portion that contacts the tire surface. It is also preferable that the rotation speed of the abrasive belt 21 be faster than the rotation speed of the tire 1. In this case, the tire surface can be polished efficiently and cleanly. The rotation direction and speed of the tire 1 can also be adjusted.

The width W of the abrasive belt 21 is not particularly limited, but is preferably smaller than the contact width (distance between the left and right contact edges) of the tread 2. An example of the width W of the abrasive belt 21 is 80 to 120 mm. The abrasive belt 21 abrades the tire surface while moving in the tire axial direction, and preferably moves in the tire axial direction at a speed of less than or equal to 50% of the width W per tire rotation. The rotation axes of the drive pulley 22 and driven pulley 23 are parallel to each other and are aligned in the tire axial direction when the abrasive belt 21 is positioned on the equator of the tread 2.

The polishing device 20 is attached to a base substrate 44, which is installed at the free end of the link of the movement mechanism 40, in a state in which it can rotate and swing within a predetermined angular range. In this embodiment, a support shaft 45 erected on the base substrate 44 is inserted into a hole provided in the support frame 27 of the polishing device 20. The support shaft 45 is a cylindrical shaft extending vertically. The polishing device 20 rotates circumferentially around the support shaft 45, allowing the polishing belt 21 to swing. As a result, the polishing belt 21 abuts against the surface of the tread 2 even at both axial ends of the tire where the degree of curvature is greater.

The swing angle (the above-mentioned specified angle) of the polishing device 20 is limited by a slot 44a formed in the base substrate 44. The slot 44a is a through hole formed along an arc centered on the axis of the support shaft 45. The support frame 27 of the polishing device 20 is provided with a cam follower 28 that is inserted into the slot 44a. The cam follower 28 is movable from one end of the slot 44a in the longitudinal direction to the other end. The base substrate 44 may also be provided with a pair of clamping links for sandwiching the cam follower 28 and moving it to the center of the slot 44a. The pair of clamping links are biased in directions that move them toward each other.

As shown in FIG. 1, the movement mechanism 40 has a first link 41 extending in the Y direction, and a second link 42 and a third link 43 pivotally supported on the free end of the first link 41. As shown in FIGS. 1, 3, and 4, a base substrate 44 for mounting the polishing apparatus 20 is provided on the free ends of the second link 42 and the third link 43. The base end of the first link 41 is rotatably attached to the pedestal 11.

The movement mechanism 40 has a first cylinder 46 and a second cylinder 47 for moving the link. For example, the first cylinder 46 is a servo cylinder, and the second cylinder 47 is an air cylinder. The first cylinder 46 can move and stop at any speed under the control of the controller 50, and moves the sanding device 20 (sanding belt 21) in the X direction. The second cylinder 47 moves the sanding belt 21 in the Y direction, bringing the sanding belt 21 into contact with the tire surface or separating it from the tire surface.

In the movement mechanism 40, the rod of the first cylinder 46 is fixed to the first link 41. When the first cylinder 46 is driven, the first link 41 rotates around its base end, causing the free end of the first link 41 to move in the X direction. The cylinder tube of the second cylinder 47 is fixed to the first link 41, and the piston rod of the second cylinder 47 is fixed to the second link 42. When the second cylinder 47 is driven, the second link 42 rotates around its base end (the connection point with the first link 41), and the third link 43 moves in conjunction with the second link 42.

That is, by driving the second cylinder 47, the polishing device 20 moves in the Y direction, and the polishing belt 21 is pressed against the tire surface or moved away from the tire surface. Furthermore, by driving the first cylinder 46, the polishing device 20 moves in the X direction (tire axial direction). The motor 26 of the polishing device 20 and the first cylinder 46 and second cylinder 47 of the movement mechanism 40 are driven under the control of the controller 50 (see Figure 2).

The configuration of the measuring device 30 will be described in detail below, with reference to Figures 1 and 2 as well as Figures 5 and 6 as appropriate. Figure 5 is a diagram showing measurement points for the amount of polishing on the tread surface. Figure 6 is a diagram showing a portion of the measuring device 30.

As shown in Figures 5 and 6, the measuring device 30 for measuring the amount of tire grinding acquires information regarding the amount of tire grinding by irradiating laser light at measurement points G1 and G2 on the tire surface and detecting reflected light from the tire surface to measure the distance. The measuring device 30 measures the distance from the device to the tire surface for measurement points G1 and G2. As the amount of tire grinding increases, the distance from the measuring device 30 to the tire surface increases, so the amount of tire grinding can be measured by measuring this distance using laser light.

The tire grinding apparatus 10 is configured to use the measuring device 30 to irradiate measurement points G1 and G2 on the tread surface with laser light and measure the amount of tire grinding from the difference in the measurements at each point. For example, the measuring device 30 outputs the measurements (distances) for measurement points G1 and G2 to the controller 50, which then calculates the amount of tire grinding from the difference in the measurements. Alternatively, the difference in the measurements or the amount of tire grinding may be calculated by the measuring device 30. In this embodiment, the first measurement point G1 is set on the contact surface 4 of the block 3, and the second measurement point G2 is set on the groove bottom 6.

The contact patch 4 is the area that is polished by the polishing device 20, and the groove bottom 6 is the area that is not polished. That is, the measuring device 30 irradiates laser light onto the first area that is polished by the polishing device 20 and the second area that is not polished. The heat generated by polishing the tread surface causes the tire 1 to expand, and this thermal expansion is one factor that prevents accurate measurement of the amount of polishing. However, by calculating the amount of polishing from the difference between the above-mentioned measured values at the contact patch 4 and the groove bottom 6, it is possible to accurately measure the amount of polishing. Because the tire 1 thermally expands in the same way at both the contact patch 4 and the groove bottom 6, the effects of thermal expansion can be effectively eliminated by using the difference between the above-mentioned measured values.

If the tire 1's contact patch 4 and grooves 5 are uniformly continuous around the tire, it is possible to measure the amount of tire grinding without setting measurement points G1 and G2 at specific locations on the contact patch 4 and groove bottom 6. However, if the tread pattern is complex, such as with studless tires, it is possible that the laser light that should be irradiated onto the contact patch 4 may instead be irradiated onto the groove 5, or that the laser light that should be irradiated onto the groove bottom 6 may instead be irradiated onto the contact patch 4. In such cases, it is preferable to set measurement points G1 and G2 at specific locations and perform measurements using the encoder 60.

Measurement points G1 and G2 are set manually by the user, for example. Using the input interface of the controller 50, the user sets a specific location on the contact surface 4 of the block 3 as measurement point G1, and a specific location on the groove bottom 6 as measurement point G2. In this embodiment, measurement points G1 and G2 are close to each other and aligned in the tire axial direction. The tire grinding device 10 resets the origin of the encoder 60 when measurement points G1 and G2 are located at the laser light irradiation position, for example, making it possible to detect the positional relationship of measurement points G1 and G2 with respect to the laser light irradiation position.

The tire grinding apparatus 10 may be configured so that the measuring device 30 measures the distance from the tire surface and determines measurement points G1 and G2 before grinding the tire 1. The controller 50, for example, controls the drive device 15 to rotate the tire 1, controls the measuring device 30 to measure the distance, and automatically sets measurement points G1 and G2. Generally, the point on the tread surface where the measured distance is smallest is the contact patch 4, and the point where the distance is largest is the groove bottom 6. The controller 50 may set measurement points G1 and G2 at the contact patch 4 and groove bottom 6, respectively, based on the values measured by the measuring device 30.

The measuring device 30 has a laser device (also called a sensor) that includes a laser element that emits laser light and a light-receiving element that receives the laser light (reflected light) reflected from the tire surface. The laser device can be a conventional device that is installed in a laser rangefinder. In addition to the laser element and light-receiving element, the laser device generally includes a laser driver, a light-receiving circuit, and a lens.

The measuring device 30 has a first laser device that irradiates the contact surface 4 with laser light, and a second laser device that irradiates the groove bottom 6 with laser light. The measuring device 30 is equipped with two laser devices 31a and 31b, with the laser device 31a irradiating the contact surface 4 with laser light and the laser device 31b irradiating the groove bottom 6 with laser light. Note that the laser device 31a may irradiate the groove bottom 6 with laser light, and the laser device 31b may irradiate the contact surface 4 with laser light.

In this embodiment, two laser devices 31a, 31b are used to measure the amount of tire grinding, but it is also possible to use a single laser device and move it axially to irradiate the contact patch 4 and groove bottom 6 with laser light, measuring the distance at each measurement point. Alternatively, three or more laser devices may be used. Furthermore, distance measurements may be performed by setting two or more measurement points on the contact patch 4, and the amount of tire grinding may be calculated from the average, median, or mode of each measurement value. Similarly, two or more measurement points may be set on the groove bottom 6.

The laser devices 31a and 31b have openings 32a and 32b through which laser light is emitted. The openings 32a and 32b are the laser light exit ports and also the entrance ports through which reflected light enters. The openings 32a and 32b are provided with a translucent cover, such as a glass cover. As will be described in more detail below, rubber debris generated when grinding the tire 1 may adhere to the covers of the openings 32a and 32b. Therefore, the measuring device 30 is provided with air nozzles 36a and 36b for blowing away the rubber debris.

The measuring device 30 has frames 33a and 33b that hold the laser devices 31a and 31b, respectively. In the example shown in Figure 6, the laser devices 31a and 31b are fixed to the lower part of the plate-shaped frames 33a and 33b, respectively. Furthermore, a total of four air nozzles, two on each side, are provided on the upper part of the frames 33a and 33b. While Figure 6 only shows the front part of the measuring device 30 facing the tire 1, the rear of the frames 33a and 33b are provided with, for example, pipes connecting the blower body and the air nozzles, and mounting brackets for the guide rails 38 described below.

The measurement device 30 has a moving means for moving the laser devices 31a and 31b in the X and Y directions. In the example shown in FIG. 1, two guide rails 37 and 38 are provided as the moving means. Guide rail 37 extends in the Y direction, and guide rail 38 extends in the X direction. Frames 33a and 33b are attached to guide rail 38 so that they can slide in the X direction, and guide rail 38 is attached to guide rail 37 using a clamp or the like so that it can slide in the Y direction. This allows the laser devices 31a and 31b to move along the X and Y directions. Alternatively, the laser devices 31a and 31b may be moved using a motor.

Frames 33a and 33b are not connected to each other and can move independently in the X direction. This makes it easy to position one of laser devices 31a and 31b facing block 3 and the other facing groove 5, allowing for compatibility with a variety of tread patterns. In the Y direction, the distance between laser devices 31a and 31b and the tire surface can be changed by sliding guide rail 38 along guide rail 37. There is generally an appropriate range for this distance, depending on the type of laser device, etc. When the tire grinding amount resolution is set to 0.1 mm or less, a suitable example of this distance is 100 ± 30 mm.

The measuring device 30 is positioned on the opposite side of the tire 1 from the grinding device 20. That is, the grinding device 20 and the measuring device 30 are positioned side by side in the tire radial direction, and are located at the furthest positions from each other at positions facing the surface of the tread 2. In this case, rubber debris generated by the grinding device 20 can be easily removed from measurement points G1 and G2 before they reach the laser light irradiation position. The outlets of the air nozzles 35a and 35b for blowing air onto the tire surface are positioned forward in the tire rotation direction from the laser light irradiation position.

In this embodiment, the laser device 31a and two air nozzles 35a and 36a are fixed to the frame 33a and integrated. In this case, setting up the device is easier than when the laser device and air nozzles are arranged separately. Similarly, the laser device 31b and two air nozzles 35b and 36b are fixed to the frame 33b and integrated. A first outlet is formed at the tip of the air nozzles 35a and 35b for blowing air onto the tire surface, and a second outlet is formed at the tip of the air nozzles 36a and 36b for blowing air into the openings 32a and 32b, which are the laser light emission ports.

The laser devices 31a, 31b and blower 34 of the measuring device 30 operate under the control of the controller 50 (see Figure 2). The blower 34 may be configured to blow air from the air nozzles 35a, 35b continuously or at appropriate timing, but it is preferable to blow air onto the tire surface at specific, controlled timing. In this embodiment, air is blown onto the measuring points G1, G2 after they pass the polishing position by the polishing device 20 and before they reach the laser light irradiation position by the measuring device 30.

The timing of spraying air from the air nozzles 35a, 35b is determined taking into consideration the number of rotations of the tire 1, the relationship between the nozzle outlet and the laser irradiation position of the measuring device 30, and other factors. In this embodiment, the air nozzles 35a, 35b are positioned close to the laser devices 31a, 31b, so air is sprayed, for example, a predetermined time after measurement points G1, G2 have passed the polishing position. In this case, air can be sprayed more efficiently at measurement points G1, G2.

Specifically, if the state in which measurement points G1 and G2 are present at the laser light irradiation position is defined as a rotation angle of 0° of the tire 1, air may be sprayed from air nozzles 35a and 35b when the measurement points reach a position 90° rotational angle in front of the irradiation position. The blower 34 sprays air from air nozzles 35a and 35b at the latest when measurement points G1 and G2 reach a position 10° in front of the irradiation position. For example, the blower 34 blows air from air nozzles 35a and 35b onto the tire surface for 1 to 10 seconds when measurement points G1 and G2 reach a position 10° to 90° in front of the irradiation position.

When blowing air onto at least the tire surface, the blower 34 sprays air from air nozzles 36a and 36b, blowing the air into openings 32a and 32b, which are the laser light emission ports of the laser devices 31a and 31b. As mentioned above, rubber debris generated when grinding the tire 1 may adhere to the covers provided on the openings 32a and 32b. In particular, since rubber debris blown off the tire surface tends to adhere to the covers, it is preferable to synchronize the timing of air spray from air nozzles 36a and 36b with the timing of air spray from air nozzles 35a and 35b.

The tire surface grinding pattern will be described in detail below with reference to Figures 7 to 9. Figure 7 is a flowchart showing an example of the control procedure for the tire grinding process.

As shown in FIG. 7 , to start the tire grinding process using the tire grinding apparatus 10, a pneumatic tire 1 mounted on a wheel is attached to the tire support shaft 12 (step S1). The tire support shaft 12 supports the tire 1 in a rotatable state. The tire 1 rotates when the drive unit 15 rotates the tire support shaft 12. The tire grinding apparatus 10 grinds, for example, the area of the surface of the tread 2 located between the left and right contact edges while rotating the tire 1.

Next, measurement points G1 and G2 are set on the surface of the tread 2 to measure the amount of polishing, and a polishing pattern for the tread surface is set (steps S2 and S3). Note that the order of steps S2 and S3 may be reversed. As described above, measurement points G1 and G2 may be set based on user operation or automatically. In either case, measurement points G1 and G2 are set on the contact surface 4 and groove bottom 6 of the block 3, respectively.

The setting information for measurement points G1 and G2 is stored in the memory of controller 50. At this time, the origin of encoder 60 is reset with measurement points G1 and G2 located at the laser light irradiation position, allowing encoder 60 to detect the relative positional relationship between the laser light irradiation position and measurement points G1 and G2. The information acquired by encoder 60 may be sent to controller 50, or may be sent to measuring device 30 via controller 50 or directly. Controller 50 may control measuring device 30 based on the information from encoder 60 to measure the amount of tire grinding.

The tread surface of tire 1 is polished by polishing device 20. Polishing device 20 operates based on the polishing pattern set in step S3 or a pattern selected from pre-set polishing patterns, and polishes the tread surface (step S4). Under the control of controller 50, polishing device 20 is configured to polish the tread surface while moving in the tire axial direction based on the polishing pattern previously set in step S3.

The abrasive belt 21 moves axially while in contact with the tread surface of the rotating tire 1, rotating in the opposite direction to the rotation of the tire 1 at the contact point to abrade the tread surface. The rotational speed of the tire 1, the movement speed and rotation speed of the abrasive belt 21, etc. can be set as desired, but it is preferable that the rotational speed of the abrasive belt 21 be faster than the rotational speed of the tire 1. The peripheral speed ratio between the abrasive belt 21 and the tire 1 (peripheral speed of the abrasive belt 21 / peripheral speed of the tire 1) is set, for example, to approximately several times to 150 times.

Next, before measurement points G1 and G2 move from the polishing position by polishing device 20 to the laser light irradiation position by measuring device 30, compressed air is sprayed onto measurement points G1 and G2 to remove rubber residue generated by polishing (step S5). In this embodiment, after measurement points G1 and G2 pass the polishing position and before they reach the laser light irradiation position, air is sprayed from air nozzles 35a and 35b onto measurement points G1 and G2. At the same time, air is sprayed from air nozzles 36a and 36b to blow air toward the laser light emission ports of laser devices 31a and 31b.

Next, laser devices 31a and 31b irradiate measurement points G1 and G2 with laser light, measuring the distance from each laser device to measurement points G1 and G2. The amount of tire grinding is then calculated from the difference between the measurements at measurement points G1 and G2 (step S6). In this embodiment, the difference between the measurements is set to 0 before grinding begins, and changes in the difference are monitored. Controller 50 may display the amount of tire grinding calculated from the difference between the measurements taken by measuring device 30 on a monitor such as a touch panel.

Steps S4 to S6 are repeated until the amount of tire grinding reaches the target value (No in step S7). The target value is stored in the memory of the controller 50, for example, along with the grinding pattern. When the amount of tire grinding reaches the target value (Yes in step S7), grinding of the tread surface by the grinding device 20 is stopped, and the grinding process ends (step S8). At this time, to prevent the occurrence of uneven grinding, it is preferable to continue grinding until the series of grinding patterns is completed. In other words, it is preferable not to end grinding midway through a grinding pattern, even if the amount of tire grinding reaches the target value.

Figures 8 and 9 show an example of the grinding pattern set in step S3. In the figures, Z indicates a profile plane along the surface (contact surface 4) of the tread 2. As described above, the tire grinding device 10 grinds the tread surface while moving in the axial direction of the tire based on the preset grinding pattern.

The sanding pattern illustrated in Figure 8 starts at position X2 on the tread surface, and the sanding belt 21 moves axially along the tire in the order X2 → X6 → X7 → X2 → X1 to perform sanding. The sanding pattern illustrated in Figure 9 inserts X5 between X2 and X6, and the sanding belt 21 moves axially along the tire in the order X2 → X5 → X6 → X7 → X2 → X1. Note that when the sanding belt 21 moves from X7 to X2, the pressing force of the sanding belt 21 against the tread surface is reduced so that the sanding belt 21 is just touching the tread surface. Alternatively, the sanding belt 21 may be moved away from the tread surface.

In both the polishing patterns shown in Figures 8 and 9, the abrasive belt 21 polishes the tread surface on both axial sides of the tread 2, moving from the axially inner side to the outer side. Research by the inventors has shown that polishing near the contact edge by moving the abrasive belt 21 from the axially outer side to the inner side, such as from X1 to X2, is likely to result in uneven polishing. In contrast, polishing while moving the abrasive belt 21 from X6 to X7 and X2 to X1 effectively reduces uneven polishing, significantly improving the polished state of the tread surface. This polishing pattern allows the entire desired polishing area to be polished cleanly and without uneven polishing.

X1, X2, X5, X6, and X7 on the tread surface are coordinates (X coordinates) used to control the position of the abrasive belt 21 in contact with the tread surface, and can be set to any position. The abrasive belt 21 moves in the tire axial direction so that the center of the belt's width is positioned on the specified X coordinate. The number of X coordinates defining the abrasive pattern is, for example, 4 to 7. An example of X1 and X7 is a position corresponding to the left and right contact edges of the tread 2. An example of X2 and X6 is a position where the curvature of the profile surface Z changes between the left and right contact edges and the tread equator.

The polishing pattern includes, for example, the movement pattern of the abrasive belt 21 in the tire axial direction (X coordinate, polishing order, etc.), as well as the rotation direction and speed of the tire 1, the rotation direction and speed of the abrasive belt 21, the pressing force of the abrasive belt 21 against the surface of the tread 2, and the target polishing amount. In this embodiment, the above parameters that make up the polishing pattern are set and stored in memory by the user operating the input interface. Multiple polishing patterns may be stored in memory. With the tire polishing device 10, the user can select the desired polishing pattern from multiple patterns by operating the input interface.

The pressure P2 shown in Figure 8 is the pressing force (sanding pressure) of the sanding belt 21 against the tread surface when the sanding belt 21 moves from X2 to X6. The pressure P1 is the pressing force of the sanding belt 21 when the sanding belt 21 moves from X6 to X7 and from X2 to X1. P1 and P2 may be set to the same value or different values.

The number of grinding passes N2 refers to the number of grinding passes performed by the abrasive belt 21 while it moves from position X2 to X6, i.e., the number of times the tire 1 rotates during that movement. The number of grinding passes N1 refers to the number of grinding passes performed by the abrasive belt 21 while it moves from X6 to X7 and from X2 to X1. N1 and N2 may be set to the same value or different values.

The sanding device 20 may sand the tread surface by repeating the movement pattern of X2 → X6 → X7 → X2 → X1, but it is more preferable to combine it with a second movement pattern. A suitable second movement pattern is one in which the sanding belt 21 starts at position X6 and moves in the order of X6 → X2 → X1 → X6 → X7. In this case, too, the pressing force of the sanding belt 21 is set small when moving from X1 to X6, so the tread surface is not substantially sanded.

In other words, it is more preferable for the grinding device 20 to grind the tread surface by alternately repeating first and second grinding patterns in which the movement directions at the axial center of the tread 2 are opposite. In the first grinding pattern, the grinding belt 21 moves from the first ground contact edge side to the second ground contact edge side at the axial center of the tread 2 (X2 → X6). In the second grinding pattern, the grinding belt 21 moves from the second ground contact edge side to the first ground contact edge side at the axial center of the tread 2 (X6 → X2). In this case, the effect of suppressing grinding unevenness is more pronounced, and grinding accuracy can be further improved.

When switching from the first sanding pattern to the second sanding pattern, i.e., when the sanding belt 21 moves from X1 to X6, the pressing force of the sanding belt 21 is set small so that the tread surface is not substantially sanded (the same applies when switching from the second sanding pattern to the first sanding pattern). For example, the first and second sanding patterns are paired and stored as a single sanding pattern in the memory of the controller 50.

When the polishing device 20 reaches the edge of the polishing range on the tire surface, it is preferable to continue polishing until the tire 1 has rotated at least one full revolution. When the polishing belt 21 reaches the edge of the polishing range, only a portion of the tire surface at that edge in the circumferential direction of the tire has been polished. Therefore, polishing for at least one full tire revolution enables more uniform polishing. In the example shown in Figure 8, when the polishing belt 21 reaches X1 or X7, polishing is continued without moving the polishing belt 21 until the tire 1 has rotated at least one full revolution.

As mentioned above, it is preferable for the polishing device 20 to perform polishing while moving in the axial direction of the tire at a speed equal to or less than 50% of the width W of the polishing belt 21 per tire rotation. Controlling the movement speed of the polishing belt 21 in this manner can further improve polishing accuracy. In the polishing pattern shown in Figure 8, for example, the movement speed of the polishing belt 21 when moving from X2 to X6 is limited to or less than 50% of the width W of the polishing belt 21 per tire rotation.

As described above, the tire grinding device 10 with the above configuration can accurately measure the amount of grinding of the tire 1, achieving high grinding precision based on accurate measurement results. The tire grinding device 10 uses the measuring device 30 to irradiate the tire's contact patch 4 and groove bottom 6 with laser light, and measures the amount of grinding of the tire from the difference between the measured values. This effectively eliminates the effects of thermal expansion due to grinding, making it possible to accurately measure the amount of grinding.

Furthermore, by grinding the tire surface while moving axially based on the grinding pattern, the entire desired grinding area can be polished cleanly and evenly, achieving the desired grinding level with high precision. Because the tire grinding device 10 is configured to automatically grind the tire surface based on a preset grinding pattern, it not only achieves high grinding precision, but also significantly reduces the workload of the user.

The above embodiment can be modified as appropriate without impairing the objectives of the present invention. For example, the above structures of the polishing device 20, measuring device 30, and moving mechanism 40 are merely examples, and the respective structures are not limited to the above structures. Furthermore, while the above polishing pattern is effective in achieving the desired polishing level with high precision, for example, the tire surface may be polished by moving from the outer side to the inner side in the axial direction on both axial sides of the tread, as long as the objectives of the present invention are not impairing.

REFERENCE SIGNS LIST 1 Tire, 2 Tread, 3 Block, 4 Ground contact surface, 5 Groove, 6 Groove bottom, 10 Tire grinding device, 11 Frame, 12 Tire support shaft, 15 Drive device, 16, 26 Motor, 20 Grinding device, 21 Grinding belt, 22 Drive pulley, 23 Driven pulley, 24 Spring, 25 Lever, 27 Support frame, 28 Cam follower, 30 Measuring device, 31a, 31b Laser device, 32a, 32b Opening, 33a, 33b Frame, 34 Blower, 35a, 35b, 36a, 36b Air nozzle, 37, 38 Guide rail, 40 Moving mechanism, 41 First link, 42 Second link, 43 Third link, 44 Base substrate, 44a Long hole, 45 Support shaft, 46 First cylinder, 47 Second cylinder, 50 Controller, 60 Encoder, G1, G2 measurement points

Claims (7)

A drive device that rotates the tire;
a grinding device for grinding the contact surface of the tire ;
a measuring device for measuring the amount of tire grinding by irradiating a laser beam onto the tire surface including the contact patch and the grooves , detecting the reflected light from the tire surface, and measuring the distance;
an encoder connected to the tire support shaft to measure the rotation angle of the tire;
Equipped with
The measuring device is configured to irradiate the laser light onto the ground contact surface and the groove bottom, respectively, and measure the tire grinding amount from the difference between the measured values at the ground contact surface and the groove bottom,
The measuring device irradiates the laser light onto a measurement point of the tire grinding amount to be irradiated with the laser light based on information acquired by the encoder. The tire grinding device described in claim 1, wherein the measuring device includes a first laser device that irradiates the laser light onto the contact surface and a second laser device that irradiates the laser light onto the groove bottom. The tire polishing apparatus according to claim 1 or 2 , wherein the measuring device is configured to measure a distance from the tire surface and determine the measurement point before polishing the tire. A drive device that rotates the tire;
a grinding device for grinding the contact surface of the tire;
a measuring device for measuring the amount of tire grinding by irradiating a laser beam onto the tire surface including the contact patch and the grooves, detecting the reflected light from the tire surface, and measuring the distance;
Equipped with
The measuring device is configured to irradiate the laser light onto the ground contact surface and the groove bottom, respectively, and measure the tire grinding amount from the difference between the measured values at the ground contact surface and the groove bottom,
A tire grinding apparatus, wherein the measuring device is disposed on the opposite side of the tire from the grinding device. A drive device that rotates the tire;
a grinding device for grinding the contact surface of the tire;
a measuring device for measuring the amount of tire grinding by irradiating a laser beam onto the tire surface including the contact patch and the grooves, detecting the reflected light from the tire surface, and measuring the distance;
a blower including a first outlet for blowing air onto a tire surface ;
Equipped with
The measuring device is configured to irradiate the laser light onto the ground contact surface and the groove bottom, respectively, and measure the tire grinding amount from the difference between the measured values at the ground contact surface and the groove bottom,
The tire grinding device is configured such that the blower blows air onto the measurement point for measuring the amount of tire grinding irradiated with the laser light after the measurement point passes a grinding position by the grinding device and before the measurement point reaches the irradiation position of the laser light. The tire grinding apparatus according to claim 5 , wherein the blower includes a second blowing port for blowing air toward an exit port of the laser light in the measuring device. The tire grinding device according to claim 6 , wherein the blower blows air toward the laser light exit port at least when blowing air toward the tire surface.