Measurement method, measurement device, and measurement program

Abstract

To provide a measurement method, a measurement device, and a measurement program which can accurately determine the force acting on the ground plane of tires differing in hardness.SOLUTION: A measurement method for determining a force F acting on a ground plane Ts of a tire T which is in contact with a road surface 2a, includes: a force measurement step S1 of measuring a partial force Fb acting on the ground plane Ts by a plurality of force sensors 2b buried in the road surface 2a; an axial force measurement step S2 of measuring an axial force Fa of a revolving shaft 3a of the tire T by an axial force sensor 3b; an integration step S3 of integrating the partial forces Fb measured by the plurality of force sensors 2b in an area As corresponding to the road surface Ts to find an integral force Fc; a correction step S4 of finding a correction coefficient C on the basis of the integral force Fc and the axial force Fa; and a force calculation step S5 of finding the force F acting on the ground surface Ts on the basis of the partial force Fb and the correction coefficient C.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a measurement method, a measurement device, and a measurement program for determining the force acting on the contact patch of a tire. [Background technology]

[0002] Various measurement methods and devices have been proposed to accurately determine the force acting on the tire's contact patch. For example, Patent Document 1 below proposes a measurement device that can accurately measure contact patch stress by arranging a sensor main part and a sensor protrusion part at a distance from a cover member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-203717 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the measuring device of Patent Document 1, the hardness of the tire being measured can affect the range of the contact patch that can be measured with the protruding detection part, making it difficult to compare tires of different hardness.

[0005] The present invention was devised in consideration of the above-described circumstances, and its main object is to provide a measurement method, a measurement device, and a measurement program that can accurately determine the forces acting on the contact surfaces of tires with different hardnesses. [Means for solving the problem]

[0006] The present invention is a measurement method for determining the forces acting on the contact patch of a tire that is in contact with a road surface, the measurement method including: a force measurement step of measuring partial forces acting on the contact patch using a plurality of force sensors embedded in the road surface; an axial force measurement step of measuring the axial force of the rotation axis of the tire using an axial force sensor; an integration step of determining an integrated force by integrating the partial forces measured by the plurality of force sensors in an area corresponding to the contact patch; a correction step of determining a correction coefficient based on the integrated force and the axial force; and a force calculation step of determining the force acting on the contact patch based on the partial forces and the correction coefficient. [Effects of the Invention]

[0007] The measurement method of the present invention, having the above-described configuration, can accurately determine the force acting on the contact patch of tires with different hardnesses. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view schematically illustrating an embodiment of a measurement device of the present invention. [Figure 2] FIG. 1 is a partial perspective view of a road surface including a plurality of force sensors. [Figure 3] FIG. 1 is an image diagram showing an example of a concept. [Figure 4] FIG. 2 is a cross-sectional schematic view of a force sensor. [Figure 5] 1 is a flowchart illustrating an embodiment of a measurement method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a schematic cross-sectional view showing a measurement device 1 of this embodiment. As shown in Fig. 1, the measurement device 1 of this embodiment is used to determine a force F acting on a contact surface Ts of a tire T that is in contact with a road surface 2a.

[0010] The tire T has, for example, a plurality of circumferential grooves t1 extending in the tire circumferential direction and a plurality of land portions t2 separated by the circumferential grooves t1. The tire T may have, for example, a plurality of lateral grooves t3 extending in the tire axial direction. The lateral grooves t3 are provided in, for example, each of the plurality of land portions t2. The land portions t2 of the tire T may be provided with, for example, sipes (not shown). Here, a sipe is a cut having a width of less than 2 mm perpendicular to the longitudinal direction, and is distinguished from a lateral groove t3 having a groove width of 2 mm or more. However, the tire T is not limited to this embodiment.

[0011] The measurement device 1 of this embodiment includes a plurality of force sensors 2b provided on a portion of the road surface 2a, and an axial force sensor 3b provided on the rotation axis 3a of the tire T. The measurement device 1 includes, for example, a cylindrical drum 2 on which the road surface 2a is provided, a tire support device 3 equipped with the rotation axis 3a of the tire T, and a drum support device 4 for driving the drum 2 to rotate.

[0012] It is desirable that the tire support device 3 supports the tire T rotatably and axially movably. This type of measurement device 1 can measure the position of the contact patch Ts measured by the multiple force sensors 2b while changing it in the tire axial direction, and is suitable for measuring the force F acting on the entire contact patch Ts.

[0013] In this embodiment, the road surface 2a is provided on the inner peripheral surface of the drum 2. The road surface 2a is not limited to this form, and may be provided on the outer peripheral surface of the drum 2, or may be provided in a flat shape, for example. If the road surface 2a is flat, it is suitable for evaluation using an actual vehicle.

[0014] FIG. 2 is a partial perspective view of a road surface 2a including multiple force sensors 2b according to this embodiment. As shown in FIGS. 1 and 2, each of the multiple force sensors 2b according to this embodiment is intended to measure a partial force Fb acting on the contact patch Ts. Here, the partial force Fb acting on the contact patch Ts refers to a force acting on the contact patch Ts within a range that can be measured by a single force sensor 2b. Such a force sensor 2b can accurately measure a force that acts locally on the contact patch Ts of the tire T as the partial force Fb. Note that the range that can be measured by a single force sensor 2b varies depending on conditions such as the load and the hardness of the tire T.

[0015] The axial force sensor 3b of this embodiment is for measuring the axial force Fa of the rotation shaft 3a of the tire T. In the case of evaluation using an actual vehicle, the axial force sensor 3b may be provided, for example, on the axle of the actual vehicle. Such an axial force sensor 3b can measure the force F acting on the entire contact patch Ts of the tire T as a representative value.

[0016] As shown in FIG. 1, the measurement device 1 of this embodiment includes an integrating means 5 that integrates partial forces Fb measured by a plurality of force sensors 2b in an area As corresponding to the contact surface Ts to obtain an integrated force Fc.

[0017] The measurement device 1 preferably includes a correction means 6 that calculates a correction coefficient C based on the integrated force Fc and the axial force Fa, and a force calculation means 7 that calculates the force F acting on the contact surface Ts based on the partial force Fb and the correction coefficient C. Note that the integration means 5, correction means 6, and force calculation means 7 may be, for example, calculation means provided separately from the measurement device 1.

[0018] FIG. 3 is an image diagram showing an example of the concept of this embodiment. FIG. 3 is an image diagram, and the numerical values ​​and the like do not represent actual numerical values. As shown in FIG. 3, the measurement device 1 corrects the partial force Fb using the axial force Fa. Therefore, even if the range of the contact patch Ts measured by one force sensor 2b differs due to differences in hardness, the force F acting on each contact patch Ts can be calculated in a comparable manner. Therefore, the measurement device 1 of this embodiment can accurately calculate the force F acting on the contact patch Ts of tires T with different hardnesses.

[0019] 1 and 2, in a more preferred embodiment, each of the plurality of force sensors 2b is capable of measuring partial forces Fb in three mutually orthogonal directions. That is, it is desirable that each of the plurality of force sensors 2b is capable of measuring partial forces Fb in three directions: longitudinal force Fx, lateral force Fy, and ground contact pressure Fz. Such force sensors 2b are useful for accurately evaluating the force F acting on the contact patch Ts of the tire T.

[0020] Each of the plurality of force sensors 2b is, for example, a three-component force sensor. Such a force sensor 2b has an excellent balance between cost and accuracy, and can improve the cost performance of the measurement device 1.

[0021] Fig. 4 is a cross-sectional schematic diagram of a force sensor 2b. As shown in Fig. 4, each of the plurality of force sensors 2b of this embodiment includes a detection portion 2c that protrudes from the road surface 2a. Such a force sensor 2b can accurately measure the partial forces Fb in three directions acting on the contact patch Ts of the tire T, namely the longitudinal force Fx, the lateral force Fy, and the ground contact pressure Fz.

[0022] The protruding height h of the detecting portion 2c from the road surface 2a is preferably 0.1 mm or more. By setting the protruding height h to 0.1 mm or more, the partial forces Fb in three directions can be reliably measured. From this viewpoint, the protruding height h is more preferably 0.2 mm or more.

[0023] The protrusion height h of the detection portion 2c from the road surface 2a is preferably 2.0 mm or less. By setting the protrusion height h to 2.0 mm or less, the contact patch Ts of the tire T is prevented from separating from the road surface 2a, and the partial force Fb acting on the contact patch Ts can be measured with high accuracy. From this perspective, the protrusion height h is more preferably 0.5 mm or less.

[0024] For these reasons, the protrusion height h is preferably 0.1 to 2.0 mm, and more preferably 0.2 to 0.5 mm. The combination of the upper and lower limits of these numerical ranges can be selected arbitrarily.

[0025] The detection portion 2c is formed, for example, in a circular shape in a plan view. The diameter d of the detection portion 2c is preferably 2 mm or more. By making the diameter d of the detection portion 2c 2 mm or more, damage to the ground surface Ts by the detection portion 2c can be suppressed. From this viewpoint, the diameter d of the detection portion 2c is more preferably 3 mm or more, and even more preferably 4 mm or more.

[0026] The diameter d of the detection portion 2c is preferably 10 mm or less. By making the diameter d of the detection portion 2c 10 mm or less, the resolution in the tire axial direction can be increased, which is useful for accurately measuring the force F acting on the contact patch Ts of the tire T. From this perspective, the diameter d of the detection portion 2c is more preferably 8 mm or less, and even more preferably 6 mm or less.

[0027] For these reasons, the diameter d of the detection portion 2c is preferably 2 to 10 mm, more preferably 3 to 8 mm, and even more preferably 4 to 6 mm. The combination of the upper and lower limits of these numerical ranges can be selected arbitrarily.

[0028] The shape of the detection unit 2c is not limited to a circular shape, and may be, for example, an elliptical shape in a plan view, an oval shape, or a polygonal shape. If the detection unit 2c is polygonal, it is desirable that each corner be chamfered in an arc shape.

[0029] 2, the detection unit 2c preferably includes a first detection unit 2d and a second detection unit 2e that protrudes at a position spaced apart from the first detection unit 2d. Such a detection unit 2c has the road surface 2a between the first detection unit 2d and the second detection unit 2e, which reduces the number of force sensors 2b and provides excellent cost performance.

[0030] The separation distance L between the first detection unit 2d and the second detection unit 2e is preferably 10 mm or more. By setting the separation distance L to 10 mm or more, the number of force sensors 2b can be reliably reduced. From this perspective, the separation distance L is more preferably 15 mm or more, and even more preferably 20 mm or more.

[0031] The separation distance L between the first detection portion 2d and the second detection portion 2e is preferably 50 mm or less. By setting the separation distance L to 50 mm or less, the resolution in the tire axial direction can be improved. From this perspective, the separation distance L is more preferably 45 mm or less, and even more preferably 40 mm or less.

[0032] For these reasons, the separation distance L is preferably 10 to 50 mm, more preferably 15 to 45 mm, and even more preferably 20 to 40 mm. The combination of the upper and lower limits of these numerical ranges can be selected arbitrarily.

[0033] As shown in Fig. 1, it is desirable that the axial force sensor 3b be capable of measuring the axial force Fa in at least three mutually perpendicular directions. Such an axial force sensor 3b is useful for accurately measuring the force F acting on the entire contact surface Ts.

[0034] The axial force sensor 3b is, for example, a six-component force meter. Such an axial force sensor 3b is useful for accurately measuring the force F acting on the entire contact surface Ts, taking into account the distance between the position of the axial force sensor 3b and the contact surface Ts.

[0035] Next, the measurement method of this embodiment will be described with reference to FIGS. Fig. 5 is a flowchart showing the measurement method of this embodiment. As shown in Fig. 5, the measurement method of this embodiment is for determining the force F acting on the contact patch Ts of the tire T that is in contact with the road surface 2a.

[0036] The measurement method of this embodiment first performs a force measurement step S1 in which a partial force Fb acting on the contact patch Ts is measured. The force measurement step S1 is preferably performed using a plurality of force sensors 2b embedded in the road surface 2a. This force measurement step S1 can accurately measure the force acting locally on the contact patch Ts of the tire T as the partial force Fb.

[0037] In the measurement method of this embodiment, an axial force measuring step S2 for measuring the axial force Fa of the rotation shaft 3a of the tire T is performed simultaneously with the force measuring step S1. The axial force measuring step S2 is preferably performed by the axial force sensor 3b. In such an axial force measuring step S2, the force F acting on the entire contact patch Ts of the tire T can be measured as a representative value.

[0038] The measurement method of this embodiment then performs an integration step S3 in which the partial forces Fb measured by the plurality of force sensors 2b in the area As corresponding to the contact patch Ts are integrated to obtain an integrated force Fc. The integration step S3 is preferably performed by an integration means 5. Such an integration step S3 can obtain the force F acting on the entire contact patch Ts of the tire T in a short time.

[0039] The measurement method of this embodiment then performs a correction step S4 in which a correction coefficient C is calculated based on the integrated force Fc and the axial force Fa. The correction step S4 is preferably performed by the correction means 6. Such a correction step S4 compares the force F acting on the entire contact patch Ts of the tire T using the integrated force Fc and the axial force Fa, and therefore the correction coefficient C for the partial force Fb measured by the force sensor 2b can be calculated with high accuracy.

[0040] For example, the same correction coefficient C may be used for the same tire T. Such a correction coefficient C also helps to further shorten the time required for measurement.

[0041] The measurement method of this embodiment then performs a force calculation step S5 in which the force F acting on the contact patch Ts is calculated based on the partial force Fb and the correction coefficient C. The force calculation step S5 is preferably performed by the force calculation means 7. In the force calculation step S5, for example, the tire T is moved in the tire axial direction and the partial force Fb measured over the entire contact patch Ts is corrected by the correction coefficient C, thereby making it possible to calculate the force F acting over the entire contact patch Ts.

[0042] In this measurement method, the axial force Fa is used to correct the partial force Fb, so even if the range of the contact patch Ts measured by one force sensor 2b differs due to differences in hardness, the force F acting on each contact patch Ts can be calculated in a comparable manner. Therefore, the measurement method of this embodiment can accurately calculate the force F acting on the contact patch Ts of tires T with different hardnesses.

[0043] In the correction step S4, it is desirable to divide the axial force Fa by the integrated force Fc to obtain the correction coefficient C. Such a correction step S4 involves simple calculations and is useful for shortening the time required for measurement.

[0044] In the correction step S4, it is desirable to use the axial forces Fa in three mutually orthogonal directions to determine the correction coefficient C in the corresponding direction. That is, in the correction step S4 of this embodiment, the longitudinal axial force Fax is used to determine the longitudinal correction coefficient Cx, the lateral axial force Fay is used to determine the lateral correction coefficient Cy, and the vertical axial force Faz is used to determine the vertical correction coefficient Cz. This correction step S4 can accurately correct the partial force Fb acting on the contact patch Ts.

[0045] In the correction step S4, for example, one of the axial forces Fa in three mutually orthogonal directions may be used to determine the correction coefficient C for the three mutually orthogonal directions. Such a correction step S4 involves simple calculations and is useful for shortening the time required for measurement.

[0046] Next, a measurement program for executing the above-described measurement method using the measurement device 1 of this embodiment will be described with reference to Figures 1 to 5. The measurement program of this embodiment is for determining the force F acting on the contact surface Ts of the tire T that is in contact with the road surface 2a.

[0047] The measurement program of this embodiment includes a force measuring step s1 for measuring the partial force Fb acting on the contact patch Ts. The force measuring step s1 is for executing the force measuring process S1, and is preferably performed using a plurality of force sensors 2b embedded in the road surface 2a. Such a force measuring step s1 can accurately measure the force acting locally on the contact patch Ts of the tire T as the partial force Fb.

[0048] The measurement program of this embodiment includes an axial force measuring step s2 for measuring the axial force Fa of the rotation shaft 3a of the tire T. The axial force measuring step s2 is for executing the axial force measuring process S2, and is preferably performed using the axial force sensor 3b. Such an axial force measuring step s2 can measure the force F acting on the entire contact patch Ts of the tire T as a representative value.

[0049] The measurement program of this embodiment includes an integration step s3 in which partial forces Fb measured by the plurality of force sensors 2b in the area As corresponding to the contact patch Ts are integrated to obtain an integrated force Fc. The integration step s3 is for executing the integration process S3 and is preferably performed by the integration means 5. Such an integration step s3 can obtain the force F acting on the entire contact patch Ts of the tire T in a short time.

[0050] The measurement program of this embodiment includes a correction step s4 for determining a correction coefficient C based on the integrated force Fc and the axial force Fa. The correction step s4 is for executing the correction process S4 and is preferably performed by the correction means 6. Such correction step s4 compares the force F acting on the entire contact patch Ts of the tire T using the integrated force Fc and the axial force Fa, and therefore can accurately determine the correction coefficient C for the partial force Fb measured by the force sensor 2b.

[0051] The measurement program of this embodiment includes a force calculation step s5 for calculating the force F acting on the contact patch Ts based on the partial force Fb and the correction coefficient C. The force calculation step s5 is for executing the force calculation process S5 and is preferably performed by the force calculation means 7. In the force calculation step s5, for example, the tire T is moved in the tire axial direction and the partial force Fb measured over the entire contact patch Ts is corrected by the correction coefficient C, thereby making it possible to calculate the force F acting over the entire contact patch Ts.

[0052] Because this measurement program corrects the partial force Fb using the axial force Fa, even if the range of the contact patch Ts measured by one force sensor 2b differs due to differences in hardness, the force F acting on each contact patch Ts can be calculated in a comparable manner. Therefore, the measurement program of this embodiment can accurately calculate the force F acting on the contact patch Ts of tires T with different hardnesses.

[0053] Although a particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment and can be modified and practiced in various ways.

[0054] [Note] The present invention is as follows.

[0055] [Invention 1] A measurement method for determining the force acting on the contact surface of a tire that is in contact with a road surface, comprising: a force measuring step of measuring partial forces acting on the contact patch using a plurality of force sensors embedded in the road surface; an axial force measuring step of measuring an axial force of a rotation shaft of the tire by an axial force sensor; an integrating step of integrating the partial forces measured by the plurality of force sensors in an area corresponding to the contact surface to obtain an integrated force; a correction step of calculating a correction coefficient based on the integrated force and the axial force; a force calculation step of calculating a force acting on the contact surface based on the partial force and the correction coefficient. Measurement method.

[0056] [Invention 2] A measurement method according to claim 1, wherein each of the plurality of force sensors includes a detection portion that protrudes from the road surface.

[0057] [Invention 3] A measuring method according to aspect 2, wherein the detection unit includes a first detection unit and a second detection unit that protrudes at a position spaced apart from the first detection unit.

[0058] [Invention 4] each of the plurality of force sensors is capable of measuring the partial forces in three mutually orthogonal directions; 4. The measurement method according to any one of claims 1 to 3, wherein the axial force sensor is capable of measuring the axial forces in at least three directions perpendicular to each other.

[0059] [Invention 5] each of the plurality of force sensors is a three-component force sensor; 5. The measurement method according to claim 4, wherein the axial force sensor is a six-component force meter.

[0060] [Invention 6] 6. The measurement method according to claim 4 or 5, wherein the correction step uses one of the axial forces in three directions perpendicular to each other to determine the correction coefficients in the three directions perpendicular to each other.

[0061] [Invention 7] 6. The measurement method according to claim 4 or 5, wherein the correction step uses the axial forces in three directions orthogonal to one another to determine the correction coefficients in the corresponding directions.

[0062] [Invention 8] 8. The measurement method according to any one of claims 1 to 7, wherein the correction step determines the correction coefficient by dividing the axial force by the integrated force.

[0063] [Invention 9] A measuring device for determining the force acting on the contact surface of a tire that is in contact with a road surface, a plurality of force sensors for measuring partial forces acting on the contact surface; an axial force sensor for measuring an axial force of a rotation shaft of the tire; an integrating means for integrating the partial forces measured by the plurality of force sensors in an area corresponding to the contact surface to obtain an integrated force; a correction means for calculating a correction coefficient based on the integrated force and the axial force; a force calculation means for calculating a force acting on the contact surface based on the partial force and the correction coefficient, Measuring equipment.

[0064] [Invention 10] A measurement program for determining the force acting on the contact surface of a tire that is in contact with a road surface, a force measuring step of measuring partial forces acting on the road surface using a plurality of force sensors embedded in the road surface; an axial force measuring step of measuring an axial force of a rotation shaft of the tire by an axial force sensor; an integrating step of integrating the partial forces measured by the plurality of force sensors in an area corresponding to the contact surface to obtain an integrated force; a correction step of calculating a correction coefficient based on the integrated force and the axial force; a force calculation step of calculating a force acting on the contact surface based on the partial force and the correction coefficient. Measurement program. [Explanation of symbols]

[0065] 2a Road surface 2b Force sensor 3a Rotation axis 3b Axial force sensor

Claims

1. A measurement method for determining the force acting on the contact surface of a tire that is in contact with a road surface, comprising: a force measuring step of measuring partial forces acting on the contact patch using a plurality of force sensors embedded in the road surface; an axial force measuring step of measuring an axial force of a rotation shaft of the tire by an axial force sensor; an integrating step of integrating the partial forces measured by the plurality of force sensors in an area corresponding to the contact surface to obtain an integrated force; a correction step of calculating a correction coefficient based on the integrated force and the axial force; a force calculation step of calculating a force acting on the contact surface based on the partial force and the correction coefficient. Measurement method.

2. The measurement method according to claim 1 , wherein each of the plurality of force sensors includes a detection portion that protrudes from the road surface.

3. The measurement method according to claim 2 , wherein the detection unit includes a first detection unit and a second detection unit that protrudes at a position spaced apart from the first detection unit.

4. each of the plurality of force sensors is capable of measuring the partial forces in three mutually orthogonal directions; The measurement method according to claim 1 , wherein the axial force sensor is capable of measuring the axial forces in at least three directions perpendicular to each other.

5. each of the plurality of force sensors is a three-component force sensor; The measurement method according to claim 4 , wherein the axial force sensor is a six-component force sensor.

6. The measurement method according to claim 4 , wherein the correction step uses one of the axial forces in three mutually orthogonal directions to determine the correction coefficients in the three mutually orthogonal directions.

7. The measurement method according to claim 4 , wherein the correction step uses the axial forces in three mutually orthogonal directions to determine the correction coefficients in the corresponding directions.

8. 4. The measurement method according to claim 1, wherein the correction step calculates the correction coefficient by dividing the axial force by the integrated force.

9. A measuring device for determining the force acting on the contact surface of a tire that is in contact with a road surface, a plurality of force sensors for measuring partial forces acting on the contact surface; an axial force sensor for measuring an axial force of a rotation shaft of the tire; an integrating means for integrating the partial forces measured by the plurality of force sensors in an area corresponding to the contact surface to obtain an integrated force; a correction means for calculating a correction coefficient based on the integrated force and the axial force; a force calculation means for calculating a force acting on the contact surface based on the partial force and the correction coefficient, Measuring equipment.

10. A measurement program for determining the force acting on the contact surface of a tire that is in contact with a road surface, a force measuring step of measuring partial forces acting on the road surface using a plurality of force sensors embedded in the road surface; an axial force measuring step of measuring an axial force of a rotation shaft of the tire by an axial force sensor; an integrating step of integrating the partial forces measured by the plurality of force sensors in an area corresponding to the contact surface to obtain an integrated force; a correction step of calculating a correction coefficient based on the integrated force and the axial force; a force calculation step of calculating a force acting on the contact surface based on the partial force and the correction coefficient. Measurement program.

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