JP6805722B2 - Tread shape measuring method and tread shape measuring device - Google Patents

Description

The present invention relates to a tread shape measuring method and a tread shape measuring device for measuring the tread surface shape of a tire using a non-contact laser displacement meter.

Conventionally, various devices for measuring the surface shape of the tread portion of a tire using a laser displacement meter have been proposed. For example, Patent Document 1 below discloses a device that measures the shape of a tread portion based on measured distance data while moving a laser displacement meter in the tire axial direction.

Japanese Unexamined Patent Publication No. 2001-56215

In the apparatus described in Patent Document 1, a laser displacement meter is arranged so that the axis of the laser beam is parallel to the equatorial plane of the tire. Therefore, since the side wall of the land portion divided by the circumferential groove formed on the surface of the tread portion and the axis of the laser emission light are substantially parallel to each other, the side wall is irradiated with the laser light and the reflected light is emitted. It may not be possible to detect it. Along with this, distance data was lost in the side wall region (see FIG. 9), and the shape of the land portion could not be measured accurately, and further improvement was requested.

The present invention has been devised in view of the above circumstances, and provides a tread shape measuring method and a tread shape measuring device capable of suppressing data loss in a side wall region of a land portion classified by a circumferential groove. The main purpose is that.

The first invention of the present invention is a method for measuring the surface shape of a tread portion of a tire, the first laser displacement meter in which the axis of the laser emission light is tilted at a positive angle with respect to the equatorial plane of the tire. A plurality of laser displacement meters, including a second laser displacement meter whose axis of laser emission light is tilted at a negative angle with respect to the tire equatorial plane, are moved in the tire meridional cross section in the tire axial direction. A measurement process for measuring the distance data from the displacement meter to the surface of the tread portion, the first distance data measured by the first laser displacement meter, and the second distance data measured by the second laser displacement meter. It is characterized by including a calculation step of obtaining distance data representing the surface shape of the tread portion by synthesizing and.

In the tread shape measuring method according to the present invention, it is desirable that the positive angle and the negative angle have the same absolute value.

In the tread shape measuring method according to the present invention, it is desirable that the positive angle is the angle θ formed by the laser emitting light and the laser incident light of the first laser displacement meter.

In the tread shape measuring method according to the present invention, the calculation step includes a correction step of correcting the first distance data according to the positive angle and correcting the second distance data according to the negative angle. It is desirable to include it.

In the tread shape measuring method according to the present invention, it is desirable that the correction step corrects the distance data by using the following formula.
Correction in the radial direction of the tire L2 = L1 × cosθ
L1: Distance from the reference position of the laser displacement meter measured by the laser displacement meter to the surface of the tread portion.
L2: Distance in the tire radial direction from the reference position of the laser displacement meter to the measurement point Correction in the tire axial direction Y2 = Y1 + α
α = L1 × sinθ
Y1: Distance in the tire axial direction from the reference position of the laser displacement meter before moving in the tire axial direction to the reference position of the moving laser displacement meter Y2: Measured from the reference position of the laser displacement meter Distance in the tire axial direction to the location

The second invention of the present invention is a device for measuring the surface shape of the tread portion of a tire, the first laser displacement meter in which the axis of the laser emission light is tilted at a positive angle with respect to the equatorial plane of the tire. , Multiple laser displacement meters including a second laser displacement meter whose axis of laser emission light is tilted at a negative angle with respect to the tire equatorial plane, and each laser displacement meter in the tire meridional cross section in the tire axial direction. The moving means to be moved, the first distance data from the first laser displacement meter measured by the first laser displacement meter to the surface of the tread portion, and the second laser measured by the second laser displacement meter. It is characterized by including a calculation means for synthesizing the second distance data from the displacement meter to the surface of the tread portion and obtaining the distance data representing the surface shape of the tread portion.

In the first invention of the present invention, the distance data from each laser displacement meter to the surface of the tread portion is measured by using the first laser displacement meter and the second laser displacement meter in the measurement step. In the first laser displacement meter, the axis of the laser emission light is tilted at a positive angle with respect to the tire equatorial plane, and in the second laser displacement meter, the axis of the laser emission light is tilted at a negative angle with respect to the tire equatorial plane. Be done. As a result, the shape of one side wall of the land portion divided by the circumferential groove extending in the tire circumferential direction in the tread portion is measured by the first laser displacement meter and the other side wall by the second laser displacement meter. .. Then, in the calculation process, the first distance data measured by the first laser displacement meter and the second distance data measured by the second laser displacement meter are combined to generate the distance data representing the surface shape of the tread portion. can get. As a result, the lack of distance data in the side wall region of the land portion is suppressed, and the surface shape of the tread portion including the side wall region can be measured.

In the second invention of the present invention, the distance data from each laser displacement meter to the surface of the tread portion is measured by using the first laser displacement meter and the second laser displacement meter. In the first laser displacement meter, the axis of the laser emission light is tilted at a positive angle with respect to the tire equatorial plane, and in the second laser displacement meter, the axis of the laser emission light is tilted at a negative angle with respect to the tire equatorial plane. Be done. As a result, the shape of one side wall of the land portion divided by the circumferential groove extending in the tire circumferential direction in the tread portion is measured by the first laser displacement meter and the other side wall by the second laser displacement meter. .. Then, the calculation means synthesizes the first distance data measured by the first laser displacement meter and the second distance data measured by the second laser displacement meter, and acquires the distance data representing the surface shape of the tread portion. To do. As a result, the lack of distance data in the side wall region of the land portion is suppressed, and the surface shape of the tread portion including the side wall region can be measured.

It is a perspective view which shows one Embodiment of the tread shape measuring apparatus used in the tread shape measuring method of this invention. It is a side view which shows the shape measuring part of the tread shape measuring apparatus. It is another side view which shows the shape measuring part of the tread shape measuring apparatus. It is a flowchart which shows the processing procedure of the tread shape measuring method of this invention. It is a graph which shows the 1st distance data before and after the correction. It is a graph which shows the 2nd distance data before and after the correction. It is a side view of the shape measuring part which shows the procedure of correcting the 1st distance data. It is a graph which shows the distance data obtained by synthesizing the 1st distance data and the 2nd distance data. It is a graph which shows the distance data obtained by the conventional tread shape measuring apparatus.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 shows an embodiment of a tread shape measuring device 1 (second invention) used in the tread shape measuring method (first invention) of the present invention.

The tread shape measuring device 1 of the present embodiment includes a tire support portion 2 that supports the tire 100 on which the surface shape of the tread portion 101 is measured, and a shape measuring unit 3 for measuring the surface shape of the tread portion 101 of the tire 100. And a data processing unit 4 that processes the data output from the shape measuring unit 3.

The tread shape measuring device 1 is suitable for measuring the shape of the tread portion 101 having a circumferential groove 102 extending in the tire circumferential direction.

The tire support portion 2 rotatably supports the tire 100 around the tire shaft. The tire support portion 2 rotationally drives a measurement rim (not shown) mounted on the tire 100, a support shaft 22 that rotatably supports the measurement rim around the tire shaft, and the support shaft 22 at a constant angular speed. It has a driving means (not shown) and the like. The inner space of the tire 100 mounted on the measurement rim is appropriately filled with internal pressure.

The shape measuring unit 3 includes non-contact laser displacement meters 31 and 32. The laser displacement meters 31 and 32 measure the distance data from the laser displacement meters 31 and 32 to the object to be measured by irradiating the object to be measured with a laser beam and converting the reflected light into an electric signal.

The laser displacement meters 31 and 32 and the data processing unit 4 are connected by a wired or wireless communication means (not shown). The electric signal (distance data) corresponding to the distance measured by the laser displacement meters 31 and 32 is transferred to the data processing unit (calculation means) 4.

As the data processing unit 4, for example, a computer device having a CPU (Central Processing Unit), a memory, a hard disk device, or the like can be applied. The data processing unit 4 operates according to a program stored in a hard disk device or the like. For example, the data processing unit 4 stores the distance data and the like transferred from the laser displacement meters 31 and 32, and the CPU executes various arithmetic processes, information processing, and the like to acquire the surface shape of the tread portion. ..

2 and 3 show the shape measuring unit 3. The laser displacement meters 31 and 32 are supported by the support portion 33. The support portion 33 supports the laser displacement meters 31 and 32 within the meridian cross section of the tire 100.

The support portion 33 is configured to be movable along a rail 34 arranged in the axial direction of the tire 100. The support portion 33 is driven by a driving means (not shown) to move the laser displacement meters 31 and 32 in the tire axial direction. The driving means outputs an electric signal corresponding to the moving distance of the laser displacement meters 31 and 32 in the tire axial direction to the data processing unit 4. The electric signal output by the driving means is used to calculate the shape of the tread portion 101.

By moving the laser displacement meters 31 and 32 in the tire axial direction, for example, 1 mm each in the tire axial direction while rotating the tire 100, distance data corresponding to the shape data of the entire circumference of the tread portion 101 is acquired.

As shown in FIG. 1, it is desirable that the rail 34 is configured so as to be adjustable in position in the tire radial direction of the tire 100 according to the size of the tire 100. This makes it possible to quickly measure the shape of the tread portion 101 for tires 100 of various sizes.

As shown in FIG. 2, in the first laser displacement meter 31 of the present embodiment, for example, the laser light is emitted from the irradiation unit 31a, and the laser light diffusely reflected by the measurement object is incident on the light receiving unit 31b. Detected by a light receiving element (not shown) and photoelectrically converted. When the distance from the irradiation unit 31a to the object to be measured fluctuates, the light receiving position on the light receiving element fluctuates. Therefore, the laser displacement meter 31 outputs an electric signal corresponding to the distance from the irradiation unit 31a to the object to be measured.

The first laser displacement meter 31 is arranged so that the axis of the laser irradiation light L is tilted at a positive angle with respect to the tire equatorial plane C. Tilt at a positive angle means that in FIG. 2, the laser irradiation light L of the first laser displacement meter 31 is tilted counterclockwise with respect to the tire equatorial plane C. Since the first laser displacement meter 31 is arranged so that the axis of the laser irradiation light L is tilted at a positive angle with respect to the tire equatorial plane C, the tire axial direction of the land portion 103 classified by the circumferential groove 102. The laser irradiation light L is incident on the side wall 103a on one side, and the reflected light is easily detected by the light receiving unit 31b.

As shown in FIG. 3, the second laser displacement meter 32 of the present embodiment has the same configuration as the first laser displacement meter 31, that is, has an irradiation unit 32a and a light receiving unit 32b.

The second laser displacement meter 32 is arranged so that the axis of the laser irradiation light L is tilted at a negative angle with respect to the tire equatorial plane C. Tilt at a negative angle means that the laser irradiation light L of the second laser displacement meter 32 is tilted clockwise with respect to the tire equatorial plane C in FIG. Since the second laser displacement meter 32 is arranged so that the axis of the laser irradiation light L is tilted at a negative angle, the laser is applied to the side wall 103b on one side in the tire axial direction of the land portion 103 divided by the circumferential groove 102. The irradiation light L is incident, and the reflected light is easily detected by the light receiving unit 32b.

It is desirable that the positive angle of the axis of the laser irradiation light L of the first laser displacement meter 31 and the negative angle of the axis of the laser irradiation light L of the second laser displacement meter 32 have the same absolute value. As a result, the laser irradiation light L is easily applied to the side wall 103a on one side of the land portion 103 in the tire axial direction and the side wall 103b on the other side. Further, the angles of the first laser displacement meter 31 and the second laser displacement meter 32 can be easily adjusted.

The positive angle of the axis of the laser irradiation light L of the first laser displacement meter 31 is the angle θ formed by the emitted light emitted from the irradiation unit 31a of the first laser displacement meter 31 and the incident light incident on the light receiving unit 31b. The above is desirable. A more desirable positive angle is the angle θ formed by the emitted light and the incident light. As a result, even when the width of the circumferential groove 102 is small, the laser irradiation light L of the first laser displacement meter 31 can be easily incident on the side wall 103a and the groove bottom, and the loss of distance data is further suppressed. Laser.

The absolute value of the negative angle of the axis of the laser irradiation light L of the second laser displacement meter 32 is the same as the positive angle. That is, the absolute value of the negative angle of the axis of the laser irradiation light L of the second laser displacement meter 32 is the emission light emitted from the irradiation unit 32a of the second laser displacement meter 32 and the incident light incident on the light receiving unit 32b. It is desirable that the angle between them is θ or more. A more desirable negative angle is the angle θ formed by the emitted light and the incident light.

The shape measuring unit 3 may include another laser displacement meter in addition to the first laser displacement meter 31 and the second laser displacement meter 32. For example, in the other laser displacement meter, the axis of the laser irradiation light L may be arranged parallel to the tire equatorial plane C. With such a laser displacement meter, the shape of the groove bottom can be easily measured.

FIG. 4 shows a processing procedure of the tread shape measuring method of the present invention. The tread shape measuring method includes a measuring step S1 and a calculation step S2.

In the measurement step S1, the first laser displacement meter 31 and the second laser displacement meter 32 are moved in the tire meridional cross section in the tire axial direction from the respective laser displacement meters 31 and 32 to the surface of the tread portion 101. Distance data is measured.

FIG. 5 shows the first distance data D1 measured by the first laser displacement meter 31. Since the first laser displacement meter 31 is arranged so that the axis of the laser irradiation light L is tilted at a positive angle θ with respect to the tire equatorial plane C, the side wall 103a on one side of the land portion 103 is measured. .. In the first distance data D1, the data of the side wall 103b on the other side of the land portion 103 is missing.

FIG. 6 shows the second distance data D2 measured by the second laser displacement meter 32. Since the second laser displacement meter 32 is arranged so that the axis of the laser irradiation light L is tilted at a negative angle −θ with respect to the tire equatorial plane C, the side wall 103b on the other side of the land portion 103 is measured. There is. In the second distance data D2, the data of the side wall 103a on one side of the land portion 103 is missing.

In the calculation step S2, the data processing unit 4 synthesizes the first distance data D1 and the second distance data D2. As a result, one distance data representing the surface shape of the tread portion 101 can be obtained.

In the present embodiment, since the first laser displacement meter 31 and the second laser displacement meter 32 are arranged at an angle with respect to the tire equatorial plane C, they are output from the first laser displacement meter 31 and the second laser displacement meter 32. It is desirable to correct the above values according to the inclination of the axis of the laser irradiation light L and then synthesize them.

That is, in the calculation step S2, the first distance data D1 measured by the first laser displacement meter 31 is corrected according to the positive angle θ, and the second distance data D2 measured by the second laser displacement meter 32 is negative. Includes a correction step that corrects according to the angle −θ of.

FIG. 7 shows a procedure for correcting the first distance data D1 measured by the first laser displacement meter 31. In the correction step, the data processing unit 4 corrects the first distance data D1 using the following formula.
Correction in the radial direction of the tire L2 = L1 × cosθ
L1: Distance from the reference position O'of the laser displacement meter during measurement to the surface of the tread (distance before correction)
L2: Distance in the radial direction of the tire from the reference position O'of the laser displacement meter during measurement to the measurement point (distance after correction)
Tire axial correction Y2 = Y1 + α
α = L1 × sinθ
Y1: Distance in the tire axial direction from the reference position O of the laser displacement meter before moving in the tire axial direction to the reference position O'of the laser displacement meter being measured (distance before correction).
Y2: Distance in the tire axial direction from the reference position O of the laser displacement meter before moving in the tire axial direction to the measurement point (distance after correction)
The second distance data D2 is also corrected in the same manner as the first distance data D1.

In FIGS. 5 and 6, the first distance data D11 and the second distance data D12 after the correction are shown together with the first distance data D1 and the second distance data D2 before the correction. Then, the data processing unit 4 synthesizes the corrected first distance data D11 and the corrected second distance data D12 to calculate one distance data representing the surface shape of the tread portion 101.

FIG. 8 shows the distance data D20 representing the surface shape of the tread portion 101 calculated by the data processing unit 4. In the present embodiment, since the first laser displacement meter 31 and the second laser displacement meter 32 are arranged so as to be tilted in opposite directions with respect to the tire equatorial plane C, the distance at which the side wall region of the land portion is not missing. Data D20 is acquired.

Although the particularly preferable embodiments of the present invention have been described in detail above, the present invention is not limited to the illustrated embodiments and can be modified into various embodiments.

Using the tread shape measuring device shown in FIG. 1, a pneumatic tire of size: 255 / 55R18 was mounted on a 9 × 18 rim, and the shape of the tread portion was measured under the condition of internal pressure: 250 kPa. A laser displacement meter manufactured by KEYENCE: LKG-150 was used for the first laser displacement meter and the second laser displacement meter. In the first laser displacement meter, the axis of the laser emission light is tilted by + 17 ° with respect to the tire equatorial plane, and in the second laser displacement meter, the axis of the laser emission light is tilted by -17 ° with respect to the tire equatorial plane. It was. The first laser displacement meter and the second laser displacement meter measured the first distance data and the second distance data of 4096 points per circumference of the tire, and acquired the distance data representing the surface shape of the tread portion shown in FIG. .. As a comparative example, distance data measured using a single laser displacement meter arranged so that the axis of the laser beam is parallel to the equatorial plane of the tire is shown in FIG.

As is clear from FIGS. 8 and 9, it was confirmed that the tread shape measuring method of the present invention can acquire distance data without loss in the side wall region of the land portion as compared with the comparative example.

1 Tread shape measuring device 31 1st laser displacement meter 32 2nd laser displacement meter S1 Measuring process S2 Calculation process

Claims (6)

It is a method for measuring the surface shape of the tread part of a tire.
A first laser displacement meter in which the axis of the laser emission light is tilted at a positive angle with respect to the tire equatorial plane, and a second laser displacement meter in which the axis of the laser emission light is tilted at a negative angle with respect to the tire equatorial plane. A measurement step of measuring distance data from each displacement meter to the surface of the tread portion while moving a plurality of laser displacement meters including the above in the tire meridional cross section in the tire axial direction, and
A calculation step of synthesizing the first distance data measured by the first laser displacement meter and the second distance data measured by the second laser displacement meter to obtain distance data representing the surface shape of the tread portion. A tread shape measuring method comprising and. Tread shape measuring method of the positive angle in claim 1, wherein the absolute value is a negative angle are equal. The tread shape measuring method according to claim 2, wherein the positive angle is an angle θ formed by the laser emitting light and the laser incident light of the first laser displacement meter. The tread shape measuring method according to claim 3, wherein the calculation step includes a correction step of correcting the first distance data according to the positive angle and correcting the second distance data according to the negative angle. .. The tread shape measuring method according to claim 4, wherein the correction step corrects the distance data using the following formula.
Correction in the radial direction of the tire L2 = L1 × cosθ
L1: Distance from the reference position of the moving laser displacement meter measured by the laser displacement meter to the surface of the tread portion.
L2: Distance in the tire radial direction from the reference position of the moving laser displacement meter to the measurement point Correction in the tire axial direction Y2 = Y1 + α
α = L1 × sinθ
Y1: Distance in the tire axial direction from the reference position of the laser displacement meter before moving in the tire axial direction to the reference position of the laser displacement meter in motion Y2: The laser before moving in the tire axial direction Distance in the tire axial direction from the reference position of the displacement meter to the measurement point A device for measuring the surface shape of the tread of a tire.
A first laser displacement meter in which the axis of the laser emission light is tilted at a positive angle with respect to the tire equatorial plane, and a second laser displacement meter in which the axis of the laser emission light is tilted at a negative angle with respect to the tire equatorial plane. With multiple laser displacement meters, including
A means of moving each laser displacement meter in the tire meridian cross section in the tire axial direction,
The first distance data from the first laser displacement meter to the surface of the tread portion measured by the first laser displacement meter, and the tread portion from the second laser displacement meter measured by the second laser displacement meter. A tread shape measuring apparatus including a calculation means for obtaining distance data representing the surface shape of the tread portion by synthesizing the second distance data to the surface of the tread portion.

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