JP2016205882A - Evaluation method of air fillability, and evaluation device used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaluation method of air fillability capable of evaluating air fillability of a tubeless tire easily in a short time.SOLUTION: An evaluation method of air fillability has a support step #1 for supporting one side wall part of a tire in a single body state, a load step #2 for imposing a load determined beforehand to the tire axial direction inside on the other side wall part of the tire, a measurement step #3 for measuring a distance between heels of a pair of bead parts in the state where the load is imposed on the other side wall part, and an evaluation step #4 for evaluating air fillability on the basis of the measured distance between heels.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an evaluation method and an evaluation apparatus for evaluating air filling properties of a tubeless tire.

  Tires shipped from factories are sometimes stacked and stored in a plurality of stages in a vertical direction in a warehouse or the like in a distribution process. When such storage is performed for a long period of time, the lower tire receives the load of the upper tire and the sidewall is deformed, and the distance between the beads is reduced. In the tubeless tire, if the distance between the beads is excessively small, a gap may be formed between the rim bead sheet and the tire bead heel when the rim is assembled, and air filling may be difficult.

  Patent Document 1 below discloses an air filling device that fills air from a gap between a bead seat and a bead heel of a tire.

Japanese Utility Model Publication No. 64-16404

  However, the air filling device is large in size and difficult to spread. Therefore, it is desired to develop a tire that can maintain the air filling property even in the above-described storage state. For this reason, establishment of a technique that can easily evaluate the air filling property of the tubeless tire is required in a short time. .

  The present invention has been devised in view of the above circumstances, and has as its main object to provide an air filling property evaluation method and an evaluation device that can easily and easily evaluate the air filling property of a tubeless tire. .

  The present invention is a method for evaluating the air-filling property of a tubeless tire, the supporting step of supporting one sidewall portion of the tire in a single state, and the other sidewall portion of the tire in the tire axial direction Based on a load step of applying a predetermined load to the inside, a measurement step of measuring a distance between a pair of bead portions in a state where the load is applied to the other sidewall portion, and the measured interval And an evaluation step for evaluating the air filling property.

  In the evaluation method according to the present invention, the evaluation step compares the measured interval with a distance in the tire axial direction between inner ends in a tire axial direction of a pair of bead seat portions of a rim in which the tire is incorporated. It is desirable.

  In the evaluation method according to the present invention, it is desirable that the measurement step measures a plurality of intervals in the tire circumferential direction.

  The present invention is an apparatus for evaluating the air-filling property of a tubeless tire, and includes a supporting means for supporting one sidewall portion of the tire in a single state, and a tire axial direction on the other sidewall portion of the tire. A load means for applying a predetermined load to the inside, and a measurement means for measuring a distance between the pair of bead portions in a state where the load is applied to the other sidewall portion.

  In the evaluation apparatus according to the present invention, the load means includes a ring member having a through hole in a central portion, and the ring member is in contact with the other sidewall portion continuously in a tire circumferential direction, The other sidewall portion is pressed inward in the tire axial direction, and the measuring means is positioned between the ring member and the supporting means via the through hole and inside the tire radial direction of the bead portion. It is desirable.

  In the evaluation apparatus according to the present invention, it is desirable that an outer diameter of the ring member is 500 to 820 mm.

  In the evaluation apparatus according to the present invention, it is desirable that an inner diameter of the ring member is 300 to 430 mm.

  In the evaluation apparatus according to the present invention, it is preferable that the measurement means includes a linear encoder.

  In the evaluation apparatus according to the present invention, it is preferable that the linear encoder is a magnetic type.

  In the air filling property evaluation method of the present invention, one sidewall portion of the tire in a single state is supported in the supporting step, and a predetermined load is applied to the other sidewall portion in the tire axial direction in the loading step. Be loaded. Thereby, the storage state of the stacked tires is reproduced in a pseudo manner. Further, in the measurement process, the distance between the pair of bead portions is measured while maintaining the pseudo storage state, and in the evaluation process, the air filling property is evaluated based on the measured distance. Therefore, it is possible to reproduce the condition of the tire after storage in a short time and measure the interval without actually stacking the tires in multiple stages and allowing the air-fillability of the tubeless tire to be evaluated in a short time and easily. Become.

  In the air-filling evaluation device of the present invention, the supporting means for supporting one sidewall portion of the tire in a single state and the loading means for applying a predetermined load to the other sidewall portion inward in the tire axial direction Thus, the storage state of the stacked tires is reproduced in a pseudo manner. Further, the distance between the pair of bead portions is measured by the measuring means while maintaining the pseudo storage state. As a result, the tire condition after storage can be reproduced in a short time and the interval can be measured without actually stacking the tires in multiple stages, and the air filling performance of the tubeless tire can be easily evaluated in a short time. become.

It is a perspective view which shows schematic structure of one Embodiment of the air-filling evaluation apparatus of this invention. It is sectional drawing of the evaluation apparatus of FIG. It is a flowchart which shows an example of the process sequence of the evaluation method of one Embodiment of this invention. It is a graph which shows transition of the space | interval of the bead part in the state in which the load was loaded on the sidewall part of the single tire. FIG. 4 is an enlarged cross-sectional view of a tire incorporated in a rim after an interval is measured in the measurement process of FIG. 3. It is sectional drawing which expands and shows the tire cross section and linear encoder vicinity of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of an evaluation apparatus 1 used for carrying out the air filling property evaluation method of the present embodiment. FIG. 2 is a cross-sectional view of the evaluation apparatus 1. As shown in FIGS. 1 and 2, the evaluation apparatus 1 according to the present embodiment supports one sidewall portion S1 of a tubeless tire (hereinafter sometimes simply referred to as a tire) A that is a measurement target. Measuring means for measuring the interval W between the pair of bead portions B1 and B2 and the supporting means 2, the load means 3 for applying a predetermined load L to the inner side in the tire axial direction on the other sidewall portion S2 of the tire A 4 is provided.

  The tire A is placed on the upper surface 2 a of the support means 2 in a sideways state, and one side wall portion S 1 is in contact with the upper surface 2 a of the support means 2 and supported by the support means 2. The support means 2 is not limited to the columnar shape shown in FIG. 1 and the like as long as it can uniformly support the sidewall portion S1 of the tire A in the tire circumferential direction. For example, it may be a flat ground.

  The load means 3 includes a ring member 31 placed on the other sidewall portion S2 of the tire A. The ring member 31 presses the sidewall portion S2 with the load L inward in the tire axial direction. The ring member 31 continuously contacts the sidewall portion S2 in the tire circumferential direction, and presses the sidewall portion S2 with a uniform load L in the tire circumferential direction.

  The load means 3 includes drive means (not shown) for generating a load L. The driving means may be hydraulic, or may be a weight placed on the upper surface of the ring member 31. When the ring member 31 has a sufficient weight, it may be its own weight.

  The measuring means 4 measures the interval W between the bead portions B1 and B2 in a state where the sidewall portion S1 is supported by the support means 2 and the load L is applied to the sidewall portion S2. The distance W between the bead portions B1 and B2 measured in the present embodiment is the distance between the heels between the heel B1a of the bead portion B1 and the heel B2a of the bead portion B2.

  The distance in the tire axial direction between the heel B1a and the toe B1c at the bead portion B1 and the distance in the tire axial direction between the heel B2a and the toe B2c at the bead portion B2 are known. Therefore, the distance between the toes between the toe B1c of the bead part B1 and the toe B2c of the bead part B2 may be measured and used as the interval W between the bead parts B1 and B2. Also, measure the heel-to-heel distance between the heel B1a of the bead part B1 and the toe B2c of the bead part B2 or the toe-heel distance between the toe B1c of the bead part B1 and the heel B2a of the bead part B2. The interval W between the bead portions B1 and B2 may be used.

  FIG. 3 shows an example of the processing procedure of the evaluation method using the evaluation apparatus 1. The evaluation method includes a supporting step (# 1) for supporting one sidewall portion S1 of the tire A in a single state, and a load L that is predetermined inward in the tire axial direction on the other sidewall portion S2 of the tire A. And a measuring step (# 3) for measuring the heel distance W between the pair of bead portions B1 and B2.

  In the support step (# 1), the tire A is placed on the upper surface 2a of the support means 2 in a lying state. Thereby, one side wall part S <b> 1 of the tire A is supported by the support means 2.

  In the loading step (# 2), the ring member 31 of the loading means 3 is placed on the sidewall portion S2 of the tire A, and a load L inward in the tire axial direction is applied to the sidewall portion S2.

  In FIG. 2, the shape of the tire A and the position of the ring member 31 in a free state before the load L is applied are two-dot chain lines, and the shape of the tire A and the position of the ring member 31 in a state where the load L is loaded are solid lines. Is shown.

  FIG. 4 shows a curve of the transition of the distance W between the heels of the bead portions B1 and B2 in a state where a load L inward in the tire axial direction is applied to the sidewall portion S2 of the single tire A. The abscissa indicates the elapsed time from the start of the load L, and the ordinate indicates the heel distance W. The load L to be applied corresponds to, for example, the load applied to the lowermost tire among the tires stacked and stored in ten stages in a warehouse in the distribution process (that is, the weight of nine tires). It is a load.

  The initial state, that is, the heel distance W before the load L is applied to the sidewall portion S2, is indicated by W0. When the load L is applied to the sidewall portion S2, the heel distance W is abruptly reduced immediately after that. The degree of decrease in the heel distance W decreases with time, and the heel distance W eventually saturates at W1. Thereafter, when the load L to the sidewall portion S2 is released and the tire A returns to the free state, the heel distance W increases from W1 to W2. At this time, the heel distance W2 is smaller than the initial heel distance W0.

  As shown in FIG. 4, the heel distance W1 substantially matches the heel distance W2 when the load L is applied to the sidewall portion S2. Therefore, by measuring the inter-heel distance W1 with the load L applied to the sidewall portion S2 using the evaluation device 1, the heel of the lowermost tire stacked in a warehouse in the distribution process in a short time It is possible to simulate the inter-distance W2 and evaluate the air filling property. Further, the heel distance W when the load L is applied to the sidewall portion S2 has a correlation with the heel distance W2 when the load is released. Therefore, the distance W between the heels with the load L applied to the sidewall portion S2 can be measured to evaluate the air filling property.

  In the measuring step (# 3) shown in FIG. 3, the heel B1a and the bead portion B2 of the bead portion B1 in a state where the sidewall portion S1 is supported by the support means 2 and the load L is applied to the sidewall portion S2. The distance W between the heel B2a and the heel B2a is measured by the measuring means 4.

  As shown in FIG. 2, when a load L is applied to the other sidewall portion S <b> 2 via the ring member 31, the other bead portion B <b> 2 on the ring member 31 side is pushed by the ring member 31. Move inward in the tire axial direction. At this time, the one sidewall portion S1 pushes the upper surface 2a of the support means 2 outward in the tire axial direction, but due to the reaction, the sidewall portion S1 is pushed back from the upper surface 2a of the support means 2 inward in the tire axial direction. It is. Since one bead part B1 on the support means 2 side is a free end, it moves inward in the tire axial direction as indicated by a solid line.

  Therefore, if the height of the heel B1a of the bead portion B1 before the movement is subtracted from the maximum width of the tire, that is, the height of the sidewall portion S2 with respect to the upper surface 2a of the support means 2, an attempt is made to estimate the inter-heel distance W. In this case, the above movement of the bead portion B1 is not taken into consideration, and an accurate heel distance W cannot be obtained. The same applies to the case where the height of the heel B1a of the bead part B1 before movement is subtracted from the height of the heel B2a of the bead part B2 with respect to the upper surface 2a of the support means 2 to estimate the heel distance W. .

  In this embodiment, since the distance between the heels W of the bead portions B1 and B2 moved inward in the tire axial direction with the load L is obtained by measurement, even if the bead portion B1 moves as described above, it is accurate. It is possible to obtain the heel distance W.

  As described above, in the loading step (# 2), the storage state of the lowermost tire stacked in a warehouse or the like is reproduced in a simulated manner, so the heel interval measured in the measurement step (# 3) The distance W approximates the heel distance W2 of the lowermost tire. Therefore, by measuring the heel distance W using the evaluation device 1, the tire state after storage is reproduced in a short time without actually stacking and leaving the tires in a plurality of stages, and the heel distance W2 Can be estimated.

  Since the heel distance W may vary in the tire circumferential direction, it is desirable to measure the heel distance W at a plurality of locations in the tire circumferential direction in the measurement step (# 3). In the present embodiment, as shown in FIG. 1, for example, the heel distance W is measured at four or more locations.

  As shown in FIG. 3, an evaluation step (# 4) for evaluating the air filling property is performed after the measurement step (# 3). In the evaluation step (# 4), the air filling property of the tubeless tire is evaluated based on the heel distance W of the tire A.

  In the evaluation process (# 4), the heel distance W measured in the measurement process (# 3) is compared with the distance between the inner ends in the tire axial direction of the pair of bead seat portions of the rim, and the air filling of the tubeless tire is performed. Sex is evaluated. The rim used in the evaluation step (# 4) is, for example, a regular rim.

  The “regular rim” is a rim determined for each tire in the standard system including the standard on which the tire is based. For example, “Standard Rim” for JATMA, “Design Rim” for TRA, ETRTO Then "Measuring Rim". Further, it may be an “applied rim” defined by JATMA.

  FIG. 5 shows the tire A incorporated in the rim R after the heel distance W is measured in the measurement step (# 3). The lumen space of the tire A is filled with air via an air valve V attached to the rim R.

  In the tubeless tire A, the heel space B1a of the bead portion B1 is in contact with the inner end R1i of the bead seat portion R1, and the heel B2a of the bead portion B2 is in contact with the inner end R2i of the bead seat portion R2. The air can be filled. Accordingly, if the distance W between the heels of the tire A incorporated in the rim R is equal to or greater than the distance WR in the tire axial direction between the inner ends R1i and R2i of the bead seat portions R1 and R2, the heel B1a is at the inner end R1i. The heel B2a abuts against the inner end R2i, and air filling is completed easily and in a short time.

  On the other hand, there is a case where air can be filled even when the distance W between the heels of the tire A is smaller than the distance WR. For example, when the air filled from the air valve V is more than the air leaking from the gap between the inner peripheral surface of the bead portions B1 and B2 and the bead seat portions R1 and R2, the pressure in the lumen space increases. Along with this, the bead portions B1 and B2 are expanded from the sidewall portions S1 and S2 to the outside in the tire axial direction, the distance W between the heels is increased, the lumen space is sealed, and air can be filled.

  In the evaluation method of the present embodiment, the distance between the heels of the lowermost tires stacked in a warehouse or the like is estimated by the distance between heels W measured in the measurement step (# 3). Therefore, in the evaluation step (# 4), the inter-heel distance W measured in the measurement step (# 3) and the pair of bead seat portions R1, R2 of the rim R in which the tire A is incorporated, the tire axial direction inner ends R1i, The distance WR in the tire axial direction between R2i is compared, and the air filling property of the tubeless tire is evaluated.

  More specifically, when the distance W between the heels of the tire A is equal to or greater than the distance WR of the rim R, it can be evaluated that air filling is easy. On the other hand, even when the heel distance W of the tire A is smaller than the distance WR of the rim R, if both are relatively approximate, the inner peripheral surface of the bead portions B1 and B2 and the bead seat portion R1, It can be evaluated that the gap with R2 is small and that air can be filled.

  In this embodiment, the distance W between the heels of the bead portions B1 and B2 moved inward in the tire axial direction with the load L in the measurement step (# 3) is measured, and the evaluation step (#) is performed based on the measured value. Since the air filling property is evaluated in 4), it is possible to make an accurate evaluation.

  The evaluation of the air filling property in the evaluation step (# 4) may be performed by a computer to which the measuring unit 4 is connected, or may be performed by an operator.

  As shown in FIGS. 1 and 2, the ring member 31 includes a ring main body 31a that abuts against the sidewall S2 and a through hole 31b formed in the center of the ring main body 31a.

  The outer diameter of the ring member 31 is preferably 500 to 820 mm. By setting the outer diameter of the ring member 31 in the above range, the ring member 31 can be brought into contact with the sidewall portion S2 of the tire for passenger cars. On the other hand, the inner diameter of the ring member 31 is desirably 300 to 430 mm. By setting the inner diameter of the ring member 31 within the above range, the inner space K in the tire radial direction of the bead portions B1 and B2 of the passenger vehicle tire can be easily accessed via the through hole 31b. The measuring means 4 for measuring the distance W between the heels is placed in the tire radial direction inner space K of the bead portions B1 and B2. The measuring means 4 is placed between the ring member 31 and the support means 2 through the through hole 31b.

  As shown in FIGS. 1 and 2, the measuring unit 4 includes two pairs of linear encoders 41 that measure a linear distance, and a support portion 42 that supports the linear encoder 41.

  The linear encoder 41 includes a linear scale portion 41a that extends linearly and a movable head portion 41b that moves along the linear scale portion 41a. In this embodiment, a magnetic linear encoder 41 called a so-called magnescale is applied.

  The linear encoder 41 is disposed in parallel to the tire axial direction so that the heel distance W of the tire A can be measured. A fine magnet in which N poles and S poles are alternately arranged is embedded in the linear scale portion 41a. The movable head portion 41b incorporates detection means for detecting a change in magnetic flux. The distance is measured based on the change in magnetic flux detected with the movement of the movable head portion 41b. In the present embodiment, the inter-heel distance W is measured by moving the movable head portion 41b from the heel B1a to the heel B2a. Note that the toe distance can also be measured by moving the movable head portion 41b from the toe B1c to the toe B2c.

  Instead of such a magnetic linear encoder 41, an optical linear encoder or a dial gauge may be applied. In the present embodiment, a magnetic linear encoder 41 that has a small error due to the influence of dust, dust, etc., and that can measure the distance quickly and easily is applied.

  The support part 42 includes a pedestal 42a placed on the upper surface 2a of the support means 2, a column part 42b erected on the pedestal 42a, and two pairs of beam parts 42c extending parallel to the upper surface 2a from the column part 42b. Have. The linear scale portion 41a of the linear encoder 41 is fixed to the tip of each beam portion 42c. The two pairs of beam portions 42c are arranged orthogonal to each other so that the two pairs of linear encoders 41 are arranged at equal intervals in the tire circumferential direction.

  FIG. 6 shows the vicinity of the linear encoder 41 in an enlarged manner. In the present embodiment, it is desirable to use a clip-shaped jig 5 for accurately measuring the heel distance W of the tire A.

  The jig 5 includes a pair of sandwiching portions 51 and 52 and a spring portion 53 that biases the sandwiching portions 51 and 52. The spring portion 53 biases the tip portions of the sandwiching portions 51 and 52 in a direction to approach them. The jig 5 is attached to the bead portion B1 or B2 so that the inner side surface 51a of the sandwiching portion 51 overlaps with the heel surface B1b of the bead portion B1 of the tire A or the heel surface B2b of the bead portion B2. .

  Using the jig 5, the linear encoder 41 measures the distance between the inner side surfaces 51a, 51a of the pair of sandwiching portions 51, 51, whereby the inter-heel distance W can be measured more accurately. .

  As mentioned above, although the evaluation method of the air filling property of this invention and the evaluation apparatus used for it were demonstrated in detail, this invention is changed and implemented in various aspects, without being limited to said specific embodiment. The

  For the three types of tires A to C, the air filling property was evaluated based on the distance between the heels. Each tire was stacked in 10 stages over 2 weeks, and then the lowermost tire was assembled with a rim, and the air filling property was tested by the operator's sensory, and the degree of agreement with the above evaluation was verified. The result is represented by an index with the air filling property of the tire C as 100, and the larger the value, the better the filling property.

  In the comparative example, a load L corresponding to the weight of nine tires is applied to the inner side in the tire axial direction by the support means 2 by the support means 2, and the maximum width of the tire, that is, the support means 2 and the ring member 31. The distance of was measured.

  In the example, the load L is supported by the support means 2 and the ring member 31 applies the load L inward in the tire axial direction, and the heel distance W of the bead portion of the tire is measured.

  As is clear from Table 1, it was confirmed that the degree of coincidence with the air filling property test in the evaluation method of the air filling property of the example was significantly improved as compared with the comparative example. For example, as shown in the example, in the tire B in which the distance between the heels W is larger than the distance between the bead seats WR even though the maximum width under load is small, the air was filled very easily. Further, even when the heel distance W was smaller than the bead sheet distance WR, the tire C having a difference of 5 mm or less was easily filled with air. On the other hand, in the tire A in which the distance between the heels W is 10 mm or more than the distance between the bead sheets WR, there is some difficulty in filling the air. On the other hand, in the comparative example, for tires A, B, and C, no clear correlation was obtained between the maximum width under load and the air filling property.

DESCRIPTION OF SYMBOLS 1 Evaluation apparatus 2 Support means 3 Load means 4 Measurement means 31 Ring member 41 Linear encoder T Tubeless tire S1, S2 Side wall part B1, B2 Bead part W Heel distance # 1 Support process # 2 Load process # 3 Measurement process # 4 Evaluation process

Claims (9)

A method for evaluating the air filling properties of a tubeless tire,
A supporting step for supporting one sidewall portion of the tire in a single state;
A load step of applying a predetermined load to the inner side in the tire axial direction on the other sidewall portion of the tire;
A measuring step of measuring a distance between a pair of bead portions in a state where the load is applied to the other sidewall portion;
And an evaluation step of evaluating air fillability based on the measured interval.   2. The air-filling property according to claim 1, wherein the evaluation step compares the measured distance with a distance in a tire axial direction between inner ends in a tire axial direction of a pair of bead seat portions of a rim in which the tire is incorporated. Evaluation method.   The air filling property evaluation method according to claim 1, wherein the measuring step measures a plurality of intervals in the tire circumferential direction. An apparatus for evaluating the air filling property of a tubeless tire,
Support means for supporting one sidewall portion of the tire in a single state;
Load means for applying a predetermined load to the inner side in the tire axial direction on the other sidewall portion of the tire;
And a measuring means for measuring a distance between a pair of bead portions in a state where the load is applied to the other sidewall portion. The load means includes a ring member having a through hole in a central portion,
The ring member is in contact with the other sidewall portion continuously in the tire circumferential direction, and presses the other sidewall portion inward in the tire axial direction,
The air filling property evaluation apparatus according to claim 4, wherein the measurement unit is positioned between the ring member and the support unit through the through hole and on the inner side in the tire radial direction of the bead portion.   The air filling property evaluation apparatus according to claim 5, wherein an outer diameter of the ring member is 500 to 820 mm.   The air filling property evaluation apparatus according to claim 5 or 6, wherein an inner diameter of the ring member is 300 to 430 mm.   The air filling property evaluation apparatus according to claim 4, wherein the measurement unit includes a linear encoder.   The air filling property evaluation apparatus according to claim 8, wherein the linear encoder is a magnetic type.

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