JPS5821506A - Method and apparatus for measuring profile of tire - Google Patents

Abstract

PURPOSE:To measure the profile quickly and highly accurately, by approximately aligning the rotary shaft line of the tire and the center of the cross section of the tire to be tested, rotating the tire, and irradiating a laser light beam from the specified direction. CONSTITUTION:XY tables 14a and 14b are provided on a flat plate 12 which is rotatably supported around the rotary shaft 10 on a supporting table 8. The tire 30 is supported thereon by a supporting post 16. The center A of the cross section of the tire 30 is approximately aligned with the rotary shaft line 0-0. An equator surface U is made in parallel with the rotary shaft line 0-0. Then the tire is rotated by an angle thetamin which is formed by the central part of a tread (not shown) and the bead part, with the rotary shaft line 0-0 as a center. Thereafter the laser light 3 is irradiated from a laser displacement gage 2 on the outer surface of the tire 30. Based on the displacement amount of an irradiated point P and the rotary angle theta, the coordinates of the irradiated point P with the rotary shaft line 0-0 as an original point is computed by an operator 4, and the profile of the tire is displayed on a display 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tire profile measuring method and a measuring device thereof, and in particular, to measuring the profile of the outer surface of a tire from the bead to the center of the tread on at least one side using a laser displacement meter. It is designed to perform measurements with high precision and in a short time.

Generally, an essential requirement for a pneumatic tire is that it should last its entire lifespan without internal failure until the rubber in the tread is completely worn out, under any usage conditions. In order to meet this requirement, it is necessary to know the stress and strain that occurs inside the tire when air is injected into the tire or when a certain load is applied to the pneumatic tire and it is pressed against a flat surface.
It must be designed so that the material strength is below the allowable limit. This internal stress and strain can be determined by calculation using the finite element method, and for this calculation, the profile of the outer surface of the pneumatic tire is traced from at least one bead portion.

Conventionally, powdered hemihydrate gypsum (CaS0 ・1/HO) has been used to measure tire profiles.
2 2 Based on this reaction, dihydrate gypsum (Ch SO4.2 H2
0) There is a method of making a mold of the tire's outer surface using a solidified material. This method has the advantage of providing highly accurate measurement results, but it requires drying and removing the molded plaster, cutting it leaving only the necessary inner surface, and then transferring it to the mold. It takes a lot of time and effort to obtain measurement results. Furthermore, in this method, the molded stone is removed from the tire for convenience.

In addition to other materials being embedded in the grooves of the tread, gypsum powder and debris adhere to the tire surface after the gypsum mold is removed, resulting in many stains on the tire.

Also, molding is done using clay etc. as a substitute for plaster.

There is a method to do this, but this method has the disadvantage that it does not provide sufficient accuracy compared to plaster.

There is also a non-contact method that uses a laser or a displacement meter to irradiate the outer surface of the tire with a laser beam and display the profile as an image.
In this type of conventional measurement method, the holding position of one tire 60 is fixed, for example, as shown in FIG. Total 4a and laser displacement meter 4
c and move the laser displacement gauges in the directions of the arrows to connect the results of measuring the tread part W and sidewall part H separately, or move the laser displacement gauge 4b diagonally in front of the shoulder part. The tread part and the sidewall part S must be measured simultaneously while moving in the direction of the arrow.
Not only does it require a lot of effort, but the accuracy is also insufficient.In the latter method, the angle of irradiation of the laser beam is not nearly perpendicular to the outer surface of the tire, which not only reduces the reflectance and results in poor accuracy. There have been problems such as the irradiation point of the laser beam may deviate from the measurable depth range of the laser displacement meter, making measurement impossible.

This invention was made in order to eliminate the above-mentioned drawbacks, and the purpose of this invention is to provide a method that can quickly and accurately measure the profile of a tire using a laser displacement needle. Another object of the present invention is to provide a measuring device that can continuously measure a wide range of tire profiles with high accuracy.

That is, in the measuring method of the present invention, as in the illustrated embodiment, the reflected light of the laser beam 3 irradiated onto the outer surface of the tire 30 is received from the laser displacement meter 2, and the profile of the tire is displayed on the display via the calculator 4. In the tire profile measurement method recorded and displayed in 6, the test tire 30
The axis of rotation -(0-0) for rotating the test tire 6o is set, the cross-sectional center A1 of the test tire 6o is almost aligned with the axis of rotation (0-0), and the equatorial plane U is aligned with the axis of rotation IJ (0-0). The test tire 30 is held parallel to the axis of rotation a (0-0) at least at the tread center F and one piece ll! The rotation trajectory of the center axis C of the test tire 60 that intersects perpendicularly to the rotation axis (0-0) and is centered on this while rotating by the angle (Qmin) between the bead portion E of the test tire 60. A laser beam 3 is irradiated onto the outer surface of the test tire 60 on the rotation axis (0-0) side from a direction intersecting with R, and the irradiation point P of the laser beam 6 corresponds to the rotation angle θ of the test tire 60.
The coordinates (Px p Py) of the irradiation point P of the laser beam 3 with the rotation axis (0-0) as the origin based on the displacement d of
The measuring device according to the present invention is characterized in that the tire holding device 1 is a rotation angle detector 11 equipped with a rotation angle detector 11. A support base 8 having a shaft 10, a flat plate 12 rotatably supported on the support base 8 around the rotating shaft 10, and a plate 12 mounted on the flat plate 12 in the length direction of the flat plate 12 and in a direction perpendicular thereto. A cross table 14 provided movably, a support 16 fixed to the cross table 14 in a direction parallel to the rotating shaft 10 of the support stand 8, and a support shaft 17 attached to the tip of the support 16 perpendicular thereto. The test tire mounting flange 20 is rotatably supported around the test tire mounting flange 20.

Embodiments of the present invention will be described below with reference to the drawings.

An embodiment of the measuring device of the present invention is shown in FIGS. 2 and 3. In the figure, numeral 1 is a tire holding device, 30 is
The test tire is held by the tire holding device 1, 2 is a laser displacement meter, 4 is a calculator, and 6 is a display.

The support base 8 of the tire holding device 1 is fixedly provided in front of the laser beam irradiation side at the laser position 2, and a rotating shaft 10 is attached to one side of the support base 8 on the laser displacement meter 2 side. The rotation axis 10 is arranged to intersect perpendicularly to the irradiation direction of the laser beam 3. Point A is the intersection of the laser beam 3 and the axis 0-0 of the rotation axis 10.

One end of a flat plate 12 is fixed to the rotating shaft 10, and the flat plate 12 is supported on the support base 8 so that it can rotate about the rotating shaft 10. Although the illustrated flat plate 12 is supported only by the rotating shaft 10, cylindrical rollers or the like may be provided between it and the support base 8 if necessary. Reference numeral 11 indicates a flat plate 120 rotation angle detector.

A cross table 14 is provided on the flat plate 12. This cross table 14 consists of an upper table 14a and a lower table 14b, and the upper table 14a is arranged in the length direction of the flat plate 12.
A sliding mechanism that slides in a direction perpendicular to the length direction of the holder 2, and a locking mechanism that fixes at an arbitrary position are provided (the sliding mechanism and the locking mechanism are not shown).

A support 16 is fixed to the cross table 12 in a direction parallel to the axis O-O of the rotating shaft 10 of the support 8.
A support shaft 17 is provided at the tip of the support shaft 17, which is perpendicular to the extension line of the laser beam 3 in the irradiation direction. This support shaft 17 has
A seven flange 20 provided with a bolt 18 is rotatably supported via a rotation mechanism (not shown). This rotation mechanism incorporates a four-wheel mechanism (not shown) that fixes the seven flange 20 at any rotational position.

Bolt 1 of 7 langes 20 of Masunari's tire holding device 1
8, when the bolt attachment part of the rim of the test tire 30 assembled with the rim is inserted and the nut is tightened, the center axis C of the test tire 30 coincides with the center of the support shaft 17 of the flange 20, and the test tire costs 300 yen. The equatorial plane U formed by the circumferential tread center line is parallel to the axis O-O of the rotating shaft 10 of the abutment 8 (
It becomes.

To measure the profile of the test tire 60, first, the test tire 30 is positioned as follows. The flat plate 12 is rotated around the rotating shaft 10, and the equatorial plane U of the test tire 30 is illuminated by the laser displacement meter 2A laser beam #
parallel to the irradiation direction in step 3. In this state, the upper table 14 & of the cross table 14 and the lower table 1
4b are slid in the length direction of the flat plate 12 and in a direction perpendicular thereto, and locked so as to substantially coincide with the cross-sectional center axis 0-0 of the test tire 60. Upper table 14
The amount of sliding of the lower table 14b varies depending on the size of the test tire 60, and the amount of sliding of the lower table 14b depends on the offset amount of the rim of the test tire 30, as shown in FIG. 4a. The center of the total width W (tread center) and the center of the height H of the sidewall portion from the tread center to the point of contact with the outer edge of the rim of the bead portion coincide with the rotational axis O-0. In this way, the cross-sectional center Ax of the test tire 60 can be positioned relatively easily.

In this state, the positional relationship of the test tire 30 with respect to the laser displacement meter 2 is such that the rotation axis O-O of the test tire 300 perpendicularly intersects the irradiation direction of the laser beam 3 of the laser displacement meter 2, and the test tire 60 The center axis A rotation locus R centered on the rotation axis O-0 intersects the irradiation direction of the laser beam 3.

If it is necessary to adjust the relative position between the irradiation direction of the laser beam 3 on the outer surface of the test tire 60 whose profile is to be measured and the tread pattern on the outer surface of the test tire 30, the seven lunges 20 of the tire holding device 1 can be adjusted. , by rotating the support shaft 17 and locking it in an appropriate position.

The positioning of the test tire 30 does not necessarily have to be carried out in the above-mentioned state, but can be carried out at any rotation angle of the flat plate 12.

Next, the principle of measurement by the method of this invention will be explained with reference to FIGS. 4 and 5.

The vertical distance between the laser displacement meter 2 and the rotation axis 10 of the support base 8 (rotation axis 0-0 of the test tire) is L1, the measured depth of the laser displacement meter 2 is D1, and the depth range is ±δ.

Irradiation point P of the laser beam 3 on the outer surface of the test tire 30
is set to be within the measurable gf range (D±δ) of the laser displacement meter 2.

With the axis of rotation 111jIO-O of the tire as the origin, the direction of the equatorial plane U of the test tire 60 (the length direction of the flat plate 12) is y
axis, the axial direction of the central axis C of the test tire 60 (direction perpendicular to the length direction of the flat plate 12) is the y-axis, and the test tire 30
The rotation angle o0 is the direction of the y-axis when the equatorial plane U of is parallel to the irradiation direction of the laser beam 3. When the test tire 60 is rotated around the rotation axis O-0 by an angle θ,
The coordinates of the irradiation point P of the laser beam 3 irradiated onto the outer surface of the test tire 60 can be determined by the following Ω calculation.

X of point P when the distance between irradiation point P and point A is 1
The coordinate px and y coordinate py are p z = L m s
inθ Py = 1 - chamber θ Between the laser displacement meter 2 and the laser beam irradiation point P (')
lj ll'+' 1lIli Ht'r Then, the measurement value by the laser displacement meter 2 (the amount of displacement of the irradiation point P with respect to the measurement depth of the laser displacement meter 2) d is d=D−T The irradiation point P The distance 1 from point A is f=L-T=L - (D-d), so Px= (L-D+d)gtnθ (1) py=
(L, -D1d)μsθ (2).

Therefore, the rotation angle θ of the test tire 300 detected by the rotation angle detector 11 and the measured value d of the laser displacement meter 2
The output signal of
, calculate the equations 1 and 2 above, and output the results to the display device (for example, an X-Y plotter or an The glophy gaps in the meridional section perpendicular to U will be recorded and displayed at an arbitrary magnification.

As described above, the test tire 60 is held at a predetermined angle 111.
By rotating the tread, it is possible to continuously measure the profile of at least 7° from the center of the tread to the peak on one side. Even with asymmetric tires, by increasing the rotation angle, it is possible to continuously measure the profile in the range from the bead on one side to the bead on the other side.

FIG. 6 is an example of profile measurement displayed as an image by the measuring device of the present invention. For laser displacement, Hikari Micro M535B (manufactured by Anritsu Electric Co., Ltd.) was used. The measurement depth of this laser displacement meter is 500 square meters, and the depth range δ is within ±40 square meters. An X-Y plotter was used as a display. Since the laser beam is irradiated from a direction almost perpendicular to the outer surface of the test tire except for the groove bottom of the tread, the reflectance is good and the contact point E with the outer edge of the rim on one side is good.
The profile from the tread center F to the contact point G with the outer edge of the rim on the other side is shown as a clear image, indicating that the measurement accuracy is high.

When measuring the profile of the meridional section of a test tire using the measurement method of the present invention, the minimum rotation angle θmin required to measure the range from the point of contact with the outer edge of the rim on at least one side to the center of the tread. (Fig. 3) differs depending on the aspect ratio of the test tire. Figure 7 shows a tire with an aspect ratio of 50%, and when determining the rotation angle θmin of this tire, the cross-sectional center of the test tire is A1.
As, K M / M N = K J / J A
t = 0.5.4KAz J = tan 0.
5 = 26.6°, /-JAI F=90', so θrnin -,4KAtF = 90°+26.6°
#・120° In the same manner, the rotation angle θmin required for a tire with an aspect ratio of 82 inches is determined as θm1n=90°+im 082#130°.

In the measurement method of the present invention, a laser beam is irradiated perpendicularly to the rotational axis 0-0 of the tire, intersecting with the rotational axis 0-0, and the irradiation direction of the laser beam is irradiated with the test tire at the rotational axis 0-0.
The relative positional relationship between the laser displacement meter and the tire holding device is set so that it intersects the rotation locus R of the center axis C of the test tire even when the test tire is rotated in a circular motion. This is one of the reasons why cross-sectional profiles can be measured with high precision.

1. When the laser beam does not intersect perpendicularly to the tire rotation axis 5O-O. For example, as shown in FIG. 8, a plane including the laser beam and the tire center axis C and the tire rotation axis O
If the intersection with 0 is A2, and the displacement of point A9 in the X-axis direction is 8, then PQ=41 is the total, instead of the length 1 of P A, which is required to calculate the coordinates of the laser beam irradiation point P. Therefore, an error as shown in the following equation occurs.

p A, =< J-+ ,', *l ) +Furthermore,
It is necessary to accurately measure the distance between the laser displacement meter 2 and the rotation axis 0-0 of the tire and input it to the calculator 4.

As is clear from the above explanation, this invention makes the axis of rotation of the tire almost coincide with the cross-sectional center of the test tire, and irradiates the test tire with a laser beam from a fixed direction while rotating the test tire. included within the range,
Moreover, since the irradiation angle of the laser beam is almost perpendicular to the outer surface of the test tire, the reflectance does not decrease, making it possible to quickly measure the profile with extremely high accuracy.

In addition, according to the tire holding device of the present invention, there is no need to move the set position of the laser displacement meter, and the positioned test tire is rotated at a predetermined angle around the center of the cross section, so the rim and size Even with different tires,
At least the profile from the bead portion to the trend portion can be measured continuously and accurately in a short time. Furthermore, even for asymmetrical panels with decorative unevenness on one sidewall, by increasing the rotation angle, the profile from the bead on one side to the bead on the other side can be made continuously and accurately. It also becomes possible to perform measurements in a short period of time.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a conventional tire profile measurement method using a laser displacement meter, FIG. 2 is a front view showing an embodiment of the measuring device of the present invention, and FIG. 3 is a plan view thereof. FIG. 4 is a plan view showing the relative position between the laser displacement needle according to the present invention and the test tire, and P and B in the figure show the relative positions when the rotation and angle of the test tire are 08 and θ, respectively. , FIG. 5 is a front view showing the relative position of the laser displacement meter according to the present invention and the test tire, and FIG. 6 is an example of tire profile measurement according to the present invention. FIG. 7 is a plan view showing the minimum necessary rotation angle, and FIG. 8 is an explanatory diagram showing an error in the direction of irradiation of the laser beam. In the figure, 1 is a tire holding device, 2 is a laser displacement meter, 6 is a laser beam, 4 is a calculator, 6 is a display, 8 is a support, 10 is a rotation axis, 11 is a rotation angle detector, and 12 is a flat plate. , 14 is a cross table, 16 is a column, 17 is a support shaft, 20 is a flange, 60 is a test tire, At is the cross-sectional center of the tire, C is the axis of rotation of the tire, E and F are the bead portions of the tire, respectively.
The center of the tread, R is the rotation trajectory of the tire center axis, 0-0
is the axis of rotation of the tire, θ is the rotation angle of the tire, θmin
is the minimum necessary rotation angle of the tire, D±δ is the measurable depth range of the laser displacement meter, P is the irradiation point of the laser beam, px
+pyti The coordinates of the irradiation point of the laser beam, d is the displacement amount of the irradiation point of the laser beam. Patent applicant Yokohama Rubber Co., Ltd. agent Patent attorney Tetsuya Mori Patent attorney Yoshiaki Naito
Masashi Shimizu0

Claims (1)

[Claims] +11 In a tire profile measuring method, the reflected light of a laser beam irradiated onto the outer surface of the tire is received from a laser displacement meter, and the tire profile is recorded and displayed on a display via a computing unit. , set a rotational axis for rotating the test tire, make the cross-sectional center of the test tire substantially coincide with the rotational axis, and make the equatorial plane parallel to the rotational axis, and rotate the test tire around the rotational axis at least at the center of the tread. While rotating the bead part on one side by an angle, the axis of rotation M of the test tire is measured from a direction perpendicular to the axis of rotation and intersecting the locus of rotation of the center axis of the test tire around this axis. 11. Irradiate the outer surface of the 1+ with a laser beam, calculate the coordinates of the laser beam irradiation point with the rotation axis as the origin based on the amount of displacement of the laser beam irradiation point corresponding to the rotation angle of the test tire, and A tire profile measuring method characterized by recording and displaying calculation results. (2) A tire holding device that holds and rotates the test tire, a laser displacement meter that irradiates the test tire with a laser beam and receives reflected light, and outputs the measured values of the laser displacement meter and the rotation angle of the test tire. an arithmetic unit that inputs a signal, and -2
A tire profile measuring device comprising a display device for recording and displaying calculation results of the arithmetic unit, wherein the tire holding device includes a support base having a rotation shaft to which a rotation angle detector is attached, and a rotation angle sensor mounted on the support base. A flat plate rotatably supported around an axis, a cross table provided on the flat plate so as to be movable in the longitudinal direction of the flat plate and in a direction orthogonal thereto, and a cross table provided on the cross table in parallel with the axis of rotation of the support. A tire characterized in that it is equipped with a support column fixed in the direction, and seven langes for mounting a test tire rotatably supported on the shaft of a support shaft attached perpendicularly to the support column at the tip of the column. Profile device.