JP2005096595A - Tire tread surface state measurement device and measurement method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire tread surface state measurement device and a measurement method capable of exactly and quickly measuring a ground-contact shape and load distribution at traveling of a vehicle in detail in the ground-contact state of the tire closing to the traveling state of an actual road surface even at high speed traveling and wetting. <P>SOLUTION: In the tire tread surface state measurement device 1A for measuring the ground-contact shape and the ground-contact force of the tire 10, a load detector 21 is constituted using an integral piezoelectric element type load cell 11a. The load detection band area 20 is constituted such that an apex surface becomes the same height as a surface 11f of a measurement road surface 11 and regarding the crossing direction of the measurement road surface 11, they are aligned and buried in a broader range than ground-contact width B1 of the stopped tire 10. Projection detectors 30 are arranged at the outside of both ends and a speed measurement device 40 for measuring traveling speed V of the tire 10 and a measurement value record device 50 for recording the measurement value in time series are provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a tire tread surface state measuring device and a measuring method for accurately measuring a force distribution in a tire ground contact surface during traveling of a vehicle.

  In tire pattern development and structure development, it is important to detect the distribution of force on the tire contact surface during high-speed driving, braking, driving, turning, and when driving the vehicle during wet conditions. There are several devices being developed.

  One of them is a device for providing a glass road surface and observing from the back side of an underground pit or the like when the tire passes over it to know the ground contact shape during tire rotation. However, although this device is effective for knowing the ground contact shape of the tire, there is a problem that it is not possible to know the distribution of force in the tread (ground road surface).

  In addition, in a low-speed road surface observation device that is a testing machine on an indoor flat plate, the vertical force is calculated from the darkness of the color of the observed ground contact portion using a detecting means whose color changes depending on the tire contact pressure. Although the force distribution is obtained, there is a problem that the force distribution in the front-rear direction and the lateral direction is not known, and measurement in a wet state or a practical speed cannot be performed.

  In addition, as a means to know the state of the tire when the vehicle is running, a pressure-sensitive conductive rubber method that measures the ground load from a change in resistance value that changes according to the pressure of the pressure-sensitive conductive rubber, or a pressure-sensitive film that responds to the pressure There are also pressure-sensitive film systems that use changes in color and density, but these have the problem that the distribution in the ground plane cannot be obtained.

  For this purpose, a load detector that detects a three-component force load with a pressure gauge and a strain gauge embedded in the side of a solid cylindrical sensor body that deforms in response to the ground load is provided. There has been proposed a tire contact surface load measuring device including a recorder that records the three-component force load detected in Step 1 in time series (see, for example, Patent Document 1).

  However, according to this measurement method, the load is detected by detecting the deformation of the solid cylindrical sensor body with a strain gauge, and therefore, the response is slow and the measurement accuracy in high-speed running is significantly reduced. There is.

  In addition, it is necessary to fill the circumference of the sensor body with the pressure sensitive part fixed to the top so that the sensor body can be freely deformed, so that it is elastic when the tire rides. Since the body is deformed, the pressure-sensitive part protrudes and rides over the cylindrical point protrusion of the pressure-sensitive part, which is different from the ground contact state with the actual road surface. Measurement tends to be inaccurate, and ultimately, there is a problem that only the pressure at each point protrusion (pressure-sensitive portion) is known, and the actual phenomenon of the tire ground contact portion during vehicle travel cannot be captured.

  In addition, since only time-series recording is performed, there is a problem that the distribution of force within the ground contact surface cannot be obtained. Further, since it is necessary to provide a gap between the sensor main body and the sensor mounting base plate and to dispose an elastic body between them, the sensor main body cannot be disposed in close contact, and the distribution of measurement points becomes rough. There is a problem.

In addition, since it is not possible to accurately detect whether or not the tire has protruded from the arrangement portion of the pressure-sensitive portion, it is not until the analysis of the measurement value is finished whether or not the accurate measurement has been completed. Since it cannot be determined, there is a problem that a measurement experiment for obtaining necessary data cannot be performed quickly.
JP 11-142265 A

  The object of the present invention is to accurately and precisely measure the ground contact state of the tire close to the actual road surface traveling condition, and quickly detect whether or not the tire has traveled beyond the load detection band during each traveling experiment. Force distribution on the tire ground contact surface during vehicle travel, contact shape, especially change in contact shape and load distribution during high speed traveling, load distribution and longitudinal force distribution during braking and driving, contact shape during turning, An object of the present invention is to provide a tire tread surface state measuring device and a measuring method capable of accurately and in detail measuring a lateral force distribution and a contact shape, load distribution, and longitudinal force distribution when wet.

In order to achieve the above object, the tire tread state measuring device of the present invention is a tire tread state measuring device that measures the ground contact shape of the tire and the contact force on the tread with a load detector embedded in a measurement road surface.
The load detector is configured using an integrated piezoelectric element type load cell that detects a force in at least one of vertical, front-rear, and lateral directions, and the load detector is used for measuring the top surface of the load detector. The surface of the road surface is the same as the height of the road surface, and with respect to the transverse direction of the measurement road surface that is substantially perpendicular to the vehicle running direction, it is embedded in a range wider than the ground contact width of the tire when the vehicle is stationary. Configure the load detection band,
A run-out detector that detects that the tire that has traveled on the measurement road surface has protruded from the load detection band is disposed outside both ends of the load detection band, and the traveling speed when the tire passes the load detection band. And a measurement value recording device for recording the measurement values detected by the load detector in time series.

  According to the present invention, since the load detector is configured using an integrated piezoelectric element type load cell, the tire contact force can be measured quickly and at a very short time interval. Detailed data on the direction of travel can be obtained. In addition, since it is not necessary to dispose an elastic member around the load cell, the ground contact force of the tire can be measured in a state close to the actual ground contact state of the road surface. Since the load cells can be arranged in close contact with each other, the distribution of measurement points can be made fine.

  Further, according to the present invention, the measurement values detected by the load detector and recorded in time series in the measurement value recording device are used as the travel coordinates measured by the speed measurement device, and the temporal change is spatially coordinated in the tire traveling direction. It becomes possible to convert it into a change, and the ground contact shape of the tire and the ground contact force of the tread can be obtained.

  In the tire tread surface state measuring apparatus, the top surface of the load detector is arranged without gaps in the transverse direction of the measurement road surface substantially orthogonal to the vehicle traveling direction, so that the tire ground contact shape is more accurate in the transverse direction. The ground contact force of the tread can be obtained.

  Further, in the tire tread surface state measuring apparatus, when the load detector is configured with a pseudo road surface or a cut actual road surface that simulates an actual road surface formed in a rectangular shape at the top of the load detector, The state of the tread of the tire can be measured in a state close to the running state on the actual road surface.

  Further, when the protrusion detector is formed of the same load detector as the load detector or a touch panel, the protrusion detector can be configured relatively easily.

  Furthermore, if a marker device is provided on the measurement road surface to mark a part of the tire when passing so that the position of the tire in contact with the load detector can be seen, the tread pattern portion of the tire that actually passed the load detection band Can be identified.

  In addition, if a guide rail that restricts the vehicle or tire travel position is provided on the measurement road surface instead of providing an overhang detector, the travel direction and travel conditions will be limited, but the tire will surely stay within the load detection band. Can pass through.

And the tire tread surface state measuring method of the present invention for achieving the above object, in the tire tread surface state measuring apparatus,
A first step of determining whether or not it has been detected that a tire that has traveled on a measurement road surface has protruded the load detection band, based on a detection value of the protrusion detector;
A second step of determining a distance traveled by the tire during a measurement time interval detected by the load detector and recorded by the measurement value recording device from the tire running speed measured by the speed measuring device;
A third step of converting each measurement timing of the time-series measurement values measured by each of the load detectors into a traveling position of the tire in the vehicle traveling direction;
From each of the load detectors, the position in the transverse direction, the advance position corresponding to each measurement time of the time series measurement value, and the time series measurement value, the contact shape of the tire, the force in the tire tread A fourth step for determining the distribution,
In the first step, when the protrusion detector detects a protrusion of a tire, the measurement is invalidated.

  According to the present invention, it is possible to convert the sampling time of the load detector into the moving position of the tire from this traveling speed, and to convert the time series measurement values measured by the load detector into the ground contact position series. Force distribution on the ground contact road surface during running, contact shape, especially change in contact shape and load distribution during high speed running, load distribution and longitudinal force distribution during braking and driving, contact shape during turning, lateral force distribution It is possible to measure the ground contact shape, load distribution, and longitudinal force distribution when wet.

  In addition, since the measurement is invalidated when the protrusion detector detects the protrusion of the tire, the success or failure of the measurement can be determined without detailed analysis, and the entire measurement can be advanced promptly.

  In the tire tread surface measurement method, when the load detector is disposed so as to be shifted in the tire traveling direction, the travel position corresponding to each measurement timing of the time-series measurement value is determined by this shift. By configuring with a correction step for correcting, it is possible to cope with a case where the load detector is arranged to be shifted in the tire traveling direction.

  According to the tire tread surface state measuring apparatus and the measuring method of the present invention, since the load detector is configured using an integrated piezoelectric element type load cell, the response of the tire is fast and the contact force of the tire is measured at a very short time interval. As a result, it is possible to obtain detailed data on the tire traveling direction, particularly in high-speed traveling. In addition, since it is not necessary to dispose an elastic member around the load cell, the ground contact force of the tire can be measured in a state close to the actual ground contact state of the road surface. And since a load cell can be arrange | positioned closely, distribution of a measurement point can be made fine.

  In addition, the measurement value detected by the load detector and recorded in time series in the measurement value recording device can be converted into a temporal coordinate change in the tire traveling direction using the traveling speed measured by the speed measuring device. It becomes possible to obtain the ground contact shape of the tire and the ground contact force of the tread.

  Therefore, it is possible to measure accurately and in detail in the ground contact state of the tire that is close to the actual road surface traveling condition, and it is possible to quickly detect whether or not the tire during each traveling experiment has traveled beyond the load detection band. Force distribution on the tire ground contact surface at the time, contact shape, in particular, change and load distribution of the contact shape during high speed driving, load distribution and longitudinal force distribution during braking and driving, contact shape during turning, lateral force distribution, In addition, the contact shape, load distribution, and longitudinal force distribution when wet can be measured accurately and in detail, and these measurement results can be used for tire pattern development and structure development.

  Hereinafter, a tire road surface state measuring device and a measuring method according to the present invention will be described with reference to the embodiments shown in the drawings. 1 and 2 show the configuration of the load detector, and FIGS. 3 to 7 show the first to fifth embodiments of the tire road surface condition measuring device of the present invention.

  As shown in FIGS. 1 to 7, the tire road surface state measuring devices 1 </ b> A to 1 </ b> F of the present invention are load detectors 21 in which the ground contact shape of the tire (test tire) 10 and the ground contact force on the tread are embedded in the measurement road surface 11. Is a tire tread surface state measuring device that measures the load on the road surface 11 for measurement, embedded in the load detector 21 for measuring 1 to 3 component forces, and an overhang detector 30 for the tire 10; A velocity measuring device 40 and a measured value recording device 50 are included.

  This load detection band 20 is an integrated piezoelectric element type load cell that detects force in at least one of vertical (Z direction), front and rear (X direction), and lateral (Y direction) depending on the purpose of measurement. The load detector 21 configured using the above is embedded in the measurement road surface 11.

  As shown in FIGS. 1 and 2, the load detector 21 reinforces the periphery of the load cell main body 21a with an installation frame 21b such as iron, and cuts out an aluminum replica road surface 21c (FIG. 1) and an actual road surface. A road surface (cut-out actual road surface) 21d (FIG. 2) is fixed to the upper portion with a preloading bolt 21e. In other words, the load detector 21 is configured by including a pseudo road surface 21 c simulating an actual road surface or a cut actual road surface 21 d formed in a rectangular shape at the top of the load detector 21. Thereby, the state of the tread surface of the tire 10 can be measured in a state closer to the traveling state on the actual road surface. A gap 21f is provided between the load cell main body 21a and the installation frame 21b.

  The load detector 21 is fixed and embedded in a road surface 11 formed of dense-grained asphalt concrete or the like with a preloading bolt 21e. The detection output of the load cell 21 is input to the measured value recording device 50. The surface of the load detector 21, that is, the surface of the replica road surface 21c made of aluminum or the surface of the cut actual road surface 21d is disposed so as to have the same height as the road surface 11f around the load detector 21. To do.

  In the present invention, this load cell main body 21a uses a piezoelectric load cell such as piezo or crystal that has good responsiveness and does not require a flexible elastic element around the structure surface. The load can be measured in a state close to the actual phenomenon. As this piezoelectric load cell, for example, a quartz piezoelectric element three-component force sensor (load cell) manufactured by KISTLER (sold by Nippon Kistler Co., Ltd.) in Switzerland can be used.

The load detection band 20 is configured so that the top surface of the load detector 21 has the same height as the surface 11f of the surrounding measurement road surface 11 and is substantially orthogonal to the vehicle traveling direction (X direction). The measurement road surface 11 is arranged side by side in a range wider than the ground contact width B1 of the tire 10 so that there is no gap in the transverse direction (Y direction) of the measurement road surface 11 and the vehicle is stationary. The arrangement of the load detectors 21 may be a single row or a plurality of rows in the front-rear direction. A large number of load detectors 21 are required in the load detection zone 20, but in order to perform more accurate and detailed measurement, the load detector 21 having a small surface in contact with the tire 10 should be arranged. Is preferred.

  In order to determine whether or not the tire 10 that has traveled on the measurement road surface 11 has traveled outside the load detection zone 20 without protruding from the load detection zone 20, the load detection zone 20 of the tire 10 is detected. An overhang detector 30 for detecting the overhang is provided. In actual vehicle travel, the tire 10 does not necessarily pass over the load detector 21 in the load detection band 20 accurately, and the ground contact width of the tire 10 may be reduced during high speed travel. When the detector 21 is arranged only for the contact width of the tire 10, there may be a case where it cannot be determined where the tire 10 passes through the load detection band 20. Therefore, the protrusion detector 30 is arranged outside the ground contact width B of the tire 10.

  As shown in FIGS. 3 to 5, the protrusion detector 30 may be formed by using the same load detector as the load detector 21, and is constituted by a uniaxial load detector that detects only the vertical direction. May be. Moreover, as shown in FIG. 6, you may form using the touch sensor 32 which understands that the tire 10 contacted. The contact surfaces of the protrusion detectors 30 on both sides are preferably as large as possible, and if they are too small, it is impossible to distinguish between the circumferential groove and the ground contact edge of the tire 10.

  When the protrusion detectors 30 on both sides detect the pressing force of the tire 10 or the touch of the tire 10, there is a possibility that the tire 10 has traveled outside the load detection band 20. Therefore, it is judged that the total vertical load cannot be obtained accurately, and the data of this running test is not used.

  Further, the speed measuring device 40 is a means for measuring the traveling speed V when the tire 10 passes over the load detection band 20, and as shown in FIGS. 3, 5, 6, and 7, laser measurement is performed. Two sets of passage detection sensors 41 having a container 41a and a reflecting mirror 41b arranged on both sides of the traveling road surface 11 so as to sandwich the front and rear of the load detection band 20, and a measurement distance L1 with respect to the vehicle traveling direction (X direction) (for example, , 0.5 m) apart from the time t1 and t2 when the laser beam was blocked by the tire 10 in the passage detection sensors 41 and 41 (or the time when this blocking ended) and the measurement distance L1. The travel speed of the vehicle and the tire 10 (V = L1 / (t2-t1)) is calculated by a calculator (not shown).

  Further, instead of using the laser measuring instrument 41a, as shown in FIG. 4, two sets of passage detection sensors 42, 42 formed by a touch panel are provided at a distance behind the load detection band 20 by a measurement distance L2, The passage detection sensors 42 and 42 are configured to calculate the vehicle and tire travel speeds (V = L2 / (t4-t2)) from the times t3 and t4 when the tire 10 touches and the measurement distance L2. Is done. In this case, the load detection band 20 is preferably disposed so as to sandwich the load detection band 20, but as shown in FIG. 4, it may be disposed only on either the front side or the rear side (FIG. 4) of the load detection band 20. However, if the load detection band 20 and the position of the speed detection device 40 are separated from each other, a measurement error of the traveling speed V increases, which is not preferable.

  8 shows a case where the speed measuring device 40 also serves as the protrusion detector 30. As shown in FIG. 8A, the tire 10 is loaded with the width B2 and the position of the passage sensors 42, 42 formed by the touch panel. Only when the detection band 20 is passed, both the passage sensors 42 and 42 are set so as to detect the passage of the tire 10. Therefore, if any one of the passage sensors 42 does not detect the passage of the tire 10, it is determined that the tire 10 is out of the load detection band 20.

The measurement value recording device 50 records the measurement values detected by the load detector 21 constituting the load detection band 20 in time series, and the measurement values detected by the protrusion detector 30 and the velocity measurement device 4.
It is a means for recording the running speed measured at zero. The measured value recording device 50 is a data storage device composed of a computer memory or the like, and is preferably a device capable of recording at least five points while the tire 10 and the load detector 21 are in contact.

  For example, when the vehicle travels at a speed of 100 km / h and the contact length is 120 mm, it is necessary to measure every 120/5 = 24 mm in order to be able to measure 5 points. Needs to be able to measure and record measurement values at time intervals shorter than 0.864 ms.

  Furthermore, as shown in FIG. 8, a part of the tire 10, for example, a tire tread portion or a side portion is marked when passing so that the position of the tire 10 in contact with the load detector 21 can be seen on the measurement road surface 11. When the marker device 43 to be attached is provided, the tread pattern portion of the tire that has actually passed through the load detection band can be specified. In the configuration of FIG. 8, the marker unit 43 is configured by providing a brush with paint on one upper surface of the passage sensors 42, 42 formed by a touch panel.

  Next, the tire road surface state measuring apparatuses 1A to 1F according to the first to sixth embodiments of FIGS. 3 to 8 will be described.

  In the configuration of the tire road surface state measuring apparatus 1A according to the first embodiment shown in FIG. 3, ten load detectors 21 for detecting forces in two directions, up and down and front and rear, are arranged in a row in the lateral direction (direction). They are arranged side by side without a gap, and the load detection band 20 is constituted by the eight load detectors 21, and the tire protrusion detector 30 is constituted by the load detectors 21 at both ends. Further, the speed detection device 40 includes two sets of sensors, that is, a passage detection sensor 41 including a laser measuring instrument 41a and a reflecting mirror 41b, and an arithmetic unit.

  In the configuration of the tire road surface state measuring device 1B according to the second embodiment in FIG. 4, ten load detectors 21 for detecting forces in two directions, up and down and front and rear, are alternately arranged in two lateral (direction) rows. L8 is arranged side by side, the load detection zone 20 is configured by the eight load detectors 21, and the tire protrusion detector 30 is configured by the load detectors 21 at both ends. The speed detection device 40 is composed of two sets of touch panels 42 and a computing unit provided behind the load detection band 20 by a measurement distance L2.

  In the configuration of the tire road surface state measuring device 1C according to the third embodiment shown in FIG. 5, ten load detectors 21 for detecting forces in the three directions of up, down, front, back, and side are alternately arranged in two rows in the horizontal direction (direction). Are arranged side by side at a distance L4, the load detector band 20 is constituted by the eight load detectors 21, and the tire protrusion detector 30 is constituted by the load detectors 21 in the vertical direction at both ends. In addition, the speed detection apparatus 40 is comprised with two sets of sensors and the calculator of the passage detection sensor 41 which consists of the laser measuring device 41a and the reflective mirror 41b similarly to FIG.

  The configuration of the tire road surface condition measuring device 1D of the fourth embodiment in FIG. 6 is a configuration in which the replica road surface 21c and the cut actual road surface 21d are formed smaller than the load cell body 11a, and receives the force of the tire 10. Since the portions cannot be continuously arranged, a large number of load detectors 21 having a small road surface area are arranged in the lateral direction (Y direction). In this case, since the positional shift amount L5 is known, simultaneity can be maintained by shifting the distance L5 in consideration of the traveling speed V and the time axis.

In other words, 16 load detectors 21 for detecting force in three directions are arranged side by side by a distance L5 (for example, 5 mm) in five rows in the lateral direction (direction), and load detection is performed by the 16 load detectors 21. A band 20 is configured, and a touch panel 32 is provided at both ends of the load detection band 20 to configure a tire protrusion detector 30. In addition, the speed detection apparatus 40 is comprised with two sets of sensors and the calculator of the passage detection sensor 41 which consists of the laser measuring device 41a and the reflective mirror 41b similarly to FIG.

  The configuration of the tire road surface state measuring device 1E according to the fifth embodiment of FIG. 7 is a configuration in which the replica road surface 21c and the cut actual road surface 21d are formed larger than the load cell main body 11a. Therefore, it arrange | positions continuously in a horizontal direction (Y direction).

  That is, 16 load detectors 21 that detect forces in three directions are arranged in a row in the lateral direction (direction), and the load detection band 20 is configured by the 16 load detectors 21. A touch panel 32 is provided at both ends to constitute a tire protrusion detector 30. In addition, the speed detection apparatus 40 is comprised with two sets of sensors and the calculator of the passage detection sensor 41 which consists of the laser measuring device 41a and the reflective mirror 41b similarly to FIG.

  The configuration of the tire road surface state measuring device 1F of the sixth embodiment in FIG. 8 is a case where the speed measuring device also serves as a protrusion detector, and as shown in FIG. 8A, a passage sensor 42 formed by a touch panel. , 42 is set so that both the passage sensors 42, 42 detect the passage of the tire 10 only when the tire 10 passes through the load detection band 20.

  Further, in this embodiment, as shown in FIG. 8B, a marker device 43 is configured by providing a brush with paint on one upper surface of the passage sensors 42, 42 formed by a touch panel. The tire 10 that has passed over the vessel 43 is marked with paint. This paint adheres in the width direction of the tire tread portion of the tire 10 and the paint on the tread portion of the tire 10 disappears, but the paint adhered to the groove portion remains, so the distance L6 between the marker device 43 and the load detection band 20 From the traveling speed V, the tread pattern portion of the tire 10 that has actually passed through the load detection band 20 can be specified.

  Although not particularly shown, if a guide rail that restricts the travel position of the vehicle or the tire 10 is provided on the measurement road surface 11 instead of providing the overhang detector 30, the travel direction and travel conditions are limited. In addition, the tire 10 can pass through the load detection zone 20.

  Next, a tire road surface state measuring method in the tire road surface state measuring apparatuses 1A to 1F having the above-described configuration will be described.

  The vehicle is caused to travel so that the tire 10 passes on the traveling road surface 11, and the outputs of the load detector 21, the protrusion detector 30, and the speed measuring device at that time are recorded by the measured value recording device.

  In the first step of data analysis, it is determined based on the detection value of the protrusion detector 30 whether or not it has been detected that the tire 10 traveling on the measurement road surface 11 has protruded from the load detection band 20. In this determination, when the overhang detector 30 detects a force or a touch of the tire 10 and detects the overhang of the tire 10, the measurement is invalidated. In this case, this measurement is invalid and the analysis work after the second step is not performed.

  In the determination of the first step, when the protrusion detector 30 does not detect the force and the touch of the tire 10 and does not detect the protrusion of the tire 10, the ear 20 passes through the load detection band 20. The measurement is validated, and the following second to fourth steps are executed.

  In the second step, the distance traveled by the tire 10 is obtained from the tire running speed V measured by the speed measuring device 40 during the measurement time interval detected by the load detector 21 and recorded by the measured value recording device 50.

  Further, in the third step, each measurement time of the time series measurement value measured by each of the load detectors 21 is converted into a traveling position of the tire 10 in the vehicle traveling direction. That is, the sampling time of the load detector is converted into the moving position of the tire 10 from the traveling speed V, and the time series measurement values measured by the load detector 21 are converted into the ground contact position series.

  And when the load detector 21 is displaced in the front-rear direction, that is, in the tire traveling direction, a correction step provided subsequent to the third step is the amount of displacement of the load detector 21. Only the travel position corresponding to each measurement time of the time series measurement value is corrected. In other words, the measured value is shifted by the shifted distance so that the measurement value is corrected so as to have simultaneity in the direction orthogonal to the vehicle traveling direction. By configuring with this correction step, it is possible to cope with the case where the load detector 21 is arranged shifted in the tire traveling direction.

  In the fourth step, the plane coordinate position of the ground contact position series is determined from the position in the transverse direction in each of the load detectors 21 and the advance position corresponding to each measurement time of the time series measurement value. From the series measurement values, the ground contact shape of the tire and the force distribution in the tire tread are obtained. The ground contact shape can be obtained by connecting the contour line since the portion where the load detector 21 detects the force in the vertical direction is where the tire is grounded. Also, the force distribution and the vector in the tire tread are obtained by displaying the force and the vector of the time series measurement value in the plane coordinates.

  By executing each of these steps, the force distribution on the tire ground contact surface during vehicle travel, the contact shape, especially the change in the contact shape and load distribution during high speed travel, the load distribution and front / rear force distribution during braking and driving, It is possible to measure the ground contact shape, lateral force distribution during turning, and the contact shape, load distribution, and longitudinal force distribution during wetness.

  Further, in the first step, the measurement is invalidated when the protrusion detector 30 detects the protrusion of the tire 10, so that the success or failure of the measurement can be determined without detailed analysis, and the entire measurement can be advanced promptly. become.

  In the tire road surface state measuring apparatus 1A according to the first embodiment shown in FIG. 3, the measurement value is sampled at 10 kHz (0.1 ms), and the distance between the two passage detection sensors 41 and 41 (L1 = 0.5 m) is measured. If the vehicle passes at Δt, for example, 0.018 s, the traveling speed V (= L1 / Δt) can be calculated as 27.778 m / s, that is, 100 km / h. Accordingly, since the tire 10 has traveled 2.78 mm (ΔL) within 0.1 ms, the time when a certain load detector 21 detects the load, that is, the time when the tire 10 is in contact with the ground is Δt2. For example, in the case of 14.5 ms, the ground contact length Ls (= ΔL × Δt2) is 125 mm.

  When this is calculated for each load detector 21 and deployed in the tire width direction (Y direction), the time waveform is converted back to the position within the tire tread, taking into account the simultaneity. The load distribution on the tire tread surface can be obtained. FIG. 9 shows the result of the load distribution (vertical force) in the tread during traveling. Similarly, the load distribution can be obtained for the longitudinal force.

  Furthermore, it is possible to obtain the braking force distribution and the driving force distribution, assuming that the driving traveling and the braking traveling are also steady traveling in the section.

  In the tire road surface state measuring apparatus 1B of the second embodiment shown in FIG. 4, the measured value is sampled at 10 kHz (0.1 ms), and Δt, for example, between the touch sensors 42 and 42 (L2 = 0.3 m) If the vehicle passes at 0.0108 s, the traveling speed V (= L2 / Δt) can be calculated as 27.778 m / s, that is, 100 km / h.

  In the tire road surface state measuring apparatus 1B according to the second embodiment, the load detector 21 in the load detection zone 20 is disposed by being shifted by L3 (for example, 20 mm) in the front-rear direction. By correcting this, simultaneity can be maintained.

  The result of the lateral force distribution in the tread during turning is shown in FIG. Similarly, the load distribution can be obtained for the vertical force. The same applies to wet road surfaces.

  In the tire road surface state measuring apparatus 1C according to the third embodiment of FIG. 5, the measured value is sampled at 10 kHz (0.1 ms), and the distance between the two passage detection sensors 41 and 41 (L1 = 0.5 m) is measured. If the vehicle passes at Δt, for example, 0.018 s, the traveling speed V (= L1 / Δt) can be calculated as 27.778 m / s, that is, 100 km / h. Therefore, the tire 10 traveled 2.78 mm (ΔL) during 0.1 ms.

  In the tire road surface state measuring device 1C according to the third embodiment, the load detector 21 in the load detection zone 20 is disposed by being shifted by L4 (for example, 30 mm) in the front-rear direction, so that a deviation of 0.0011 s is achieved. By correcting this, simultaneity can be maintained.

  The result of the longitudinal force distribution in the tread during braking is shown in FIG. Similarly, the load distribution can be obtained for the vertical force. The same applies to wet road surfaces.

  FIG. 12 shows the results of vector display of the force distribution in the tire traveling direction (X direction) and the lateral direction (Y direction) obtained by the tire road surface condition measuring apparatus 1F of the sixth embodiment in FIG. In the tire road surface state measuring apparatus 1F, a brush 43 provided on the upper surface of the passage sensor 42 is used to attach a mark of paint to the tire 10 that has passed thereabove, so that the distance L6 between the brush 43 and the load detection band 20 and travel From the speed V, the portion of the tire 10 that has actually passed through the load detection zone 20 can be identified.

  Accordingly, since the tire contact portion on the road surface in FIG. 12 and the tread pattern of the contact portion of the tire 10 can be overlapped, more detailed information useful for tire pattern development and structure development can be obtained.

It is explanatory drawing which shows typically the structure of the load detector of embodiment of this invention. It is explanatory drawing which shows typically the structure of the load detector of other embodiment of this invention. It is a top view which shows the structure of the tire road surface state measuring apparatus of the 1st Embodiment of this invention. It is a top view which shows the structure of the tire road surface state measuring apparatus of the 2nd Embodiment of this invention. It is a top view which shows the structure of the tire road surface state measuring apparatus of the 3rd Embodiment of this invention. It is a top view which shows the structure of the tire road surface state measuring apparatus of the 4th Embodiment of this invention. It is a top view which shows the structure of the tire road surface state measuring apparatus of the 5th Embodiment of this invention. It is a top view which shows the structure of the tire road surface state measuring apparatus of the 6th Embodiment of this invention. It is a figure which shows the result of the load distribution (up-down force) in the tread during driving | running | working. It is a figure which shows the result of lateral force distribution in the tread during turning. It is a figure which shows the result of the longitudinal force distribution in the tread during braking. It is a figure which shows the result of carrying out the vector display of the distribution of force of a tire advancing direction and a horizontal direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A-1F Tire road surface state measuring apparatus 10 Tire 11 Traveling road surface 11f Road surface 20 Load detection zone 21 Load detector 21a Load cell main body 21b Installation frame 21c Replica road surface 21d Cutout actual road surface 21e Preloading bolt 21f Air gap 30 Projection detector 31 Load detection Sensor 32 Touch sensor 41a Laser measuring instrument 41b Reflector 41 Passing detection sensor (laser measuring instrument)
42 Passage detection sensor (touch panel)
50 Measurement value recording device

Claims (8)

In the tire tread condition measurement device that measures the ground contact shape of the tire and the contact force on the tread with a load detector embedded in the road surface for measurement,
The load detector is configured using an integrated piezoelectric element type load cell that detects a force in at least one of vertical, front-rear, and lateral directions, and the load detector is used for measuring the top surface of the load detector. The surface of the road surface is the same as the height of the road surface, and with respect to the transverse direction of the measurement road surface that is substantially perpendicular to the vehicle running direction, it is embedded in a range wider than the ground contact width of the tire when the vehicle is stationary. Configure the load detection band,
A run-out detector that detects that the tire that has traveled on the measurement road surface has protruded from the load detection band is disposed outside both ends of the load detection band, and the traveling speed when the tire passes the load detection band. A tire tread surface state measuring device, comprising: a speed measuring device for measuring the tire pressure; and a measured value recording device for recording the measured value detected by the load detector in time series.   2. The tire tread surface state measuring apparatus according to claim 1, wherein the top surfaces of the load detectors are arranged without a gap in a transverse direction of a measurement road surface substantially orthogonal to the vehicle traveling direction.   The load detector is configured to include a pseudo road surface or a cut out actual road surface that is formed in a rectangular shape and that simulates an actual road surface at the top of the load detector. Tire tread condition measuring device.   The tire tread surface state measuring apparatus according to any one of claims 1 to 3, wherein the protrusion detector is formed of the same load detector as the load detector or a touch panel.   The marker device for marking a part of the tire when passing so that the position of the tire in contact with the load detector can be understood on the road surface for measurement. The tire tread surface state measuring device according to 1.   The guide rail which regulates the running position of a vehicle or a tire was provided in the measurement road surface instead of providing the protrusion detector, The above-mentioned any one of Claims 1, 2, 3 or 5 characterized by the above-mentioned. Tire tread condition measuring device. In the tire tread surface state measuring device according to any one of claims 1 to 5,
A first step of determining whether or not a tire that has traveled on a measurement road surface has protruded from the load detection band based on a detection value of the protrusion detector;
A second step of determining a distance traveled by the tire during a measurement time interval detected by the load detector and recorded by the measurement value recording device from the tire running speed measured by the speed measuring device;
A third step of converting each measurement timing of the time-series measurement values measured by each of the load detectors into a traveling position of the tire in the vehicle traveling direction;
From each of the load detectors, the position in the transverse direction, the advance position corresponding to each measurement time of the time series measurement value, and the time series measurement value, the contact shape of the tire, the force in the tire tread A tire tread surface state measuring method including a fourth step for obtaining a distribution. And a correction step of correcting the traveling position corresponding to each measurement time of the time-series measurement value by an amount corresponding to the deviation when the load detector is arranged to be shifted in the tire traveling direction. Item 8. The tire tread surface state measuring method according to Item 7.

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