JP2020052019A - Method for estimating high-rate uniformity of tire - Google Patents

Abstract

To estimate a high-rate uniformity of a tire easily and precisely.SOLUTION: The method for estimating the high-speed uniformity of a tire includes: a first step S1 of acquiring a first relation between a difference ΔRRO and a static unbalance for a reference tire; a second step S2 of acquiring a second relation between a high-rate RFV, a low-rate RFV, a low-rate RRO, and a difference ΔRRO for a reference tire; a third step S3 of measuring a low-rate RFV, a low-rate RRO, and a static unbalance for an insection target tire; a fourth step S4 for applying the static unbalance measured in the third step to the first step and estimating the difference ΔRRO of the inspection target tire; and a fifth step S5 for applying the low-rate RFV and the low-rate RRO measured in the third step and the difference ΔRRO estimated by the fourth step to the second relation and estimating the high-rate RFV of the inspection target tire.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a tire high-speed uniformity estimation method capable of easily and accurately estimating a high-speed uniformity from a low-speed uniformity.

  In recent years, in order to prevent the occurrence of a vehicle vibration problem caused by tires, many tire manufacturers inspect uniformity of manufactured tires and ship conforming non-defective products. In the inspection of the uniformity, for example, measurement of an RFV (radial force variation) indicating a variation in a force in a tire radial direction (up and down) when the tire is rotated once is measured.

  The uniformity is roughly classified into a low-speed uniformity and a high-speed uniformity according to the rotation speed of the tire at the time of measurement. The low speed uniformity is measured by rotating the tire at a speed at which substantially no centrifugal force acts (at most about 60 rpm, and in the case of a tire for a passenger car, about 7 km / h). Therefore, it is possible to relatively easily measure the total number of tires using the uniformity measuring device. On the other hand, the high-speed uniformity needs to be measured in a state where the tire is rotated at a speed at which centrifugal force acts (for example, about 100 to 120 km / h). Also need a lot of time. For this reason, it is not realistic to measure the high speed uniformity for all the tires.

  Conventionally, in order to solve such a problem, a high-speed RFV is estimated using an estimation expression using a low-speed RFV and a static imbalance (for example, see Patent Document 1 below). However, in the conventional method, there is room for further improvement in the estimation accuracy of the high-speed RFV.

JP 2001-141615 A

  The present invention has been devised in view of the above problems, and has as its main object to provide a method for estimating a high-speed RFV of a tire, which can easily and accurately estimate a high-speed uniformity.

  The present invention relates to a method for estimating a high-speed uniformity of a tire, and a first relation in which a difference ΔRRO, which is a difference between a high-speed RRO and a low-speed RRO of a tread portion, and a static imbalance are related to a reference tire. A first step of acquiring, a second step of acquiring a high-speed RFV, a low-speed RFV, a low-speed RRO of the tread portion, and a second relationship in which the difference ΔRRO is associated with the reference tire; The third step of measuring the low-speed RFV, the low-speed RRO of the tread portion, and the static imbalance of the tire to be inspected whose type is unknown and the high-speed RFV is unknown, and the first relationship is measured in the third step. A fourth step of applying the static imbalance and estimating the difference ΔRRO of the tire to be inspected, and the low relation measured in the third step in the second relation. And RFV, and the low-speed RRO, and applying said difference ΔRRO estimated by the fourth step, characterized in that it comprises a fifth step of estimating the high-speed RFV of said tire to be inspected. Here, n is a natural number.

  In the estimation method, it is preferable that the first step includes a step of measuring the high-speed RRO, the low-speed RRO, and the static imbalance of the tread portion of the reference tire.

  In the estimation method, it is preferable that the second step includes a step of measuring the high-speed RFV, the low-speed RFV, and the low-speed RRO of the tread portion for the reference tire.

  In the estimation method, it is preferable that, in the first relationship, an n-order component of the difference ΔRRO is associated with an n-order component of the static imbalance. Here, n is a natural number.

  In the estimation method, the second relationship may include an nth-order component of the high-speed RFV, an nth-order component of the low-speed RFV, an nth-order component of the low-speed RRO of the tread portion, and an nth-order component of the difference ΔRRO. Is desirably associated with. Here, n is a natural number.

ただし、
ΔＲＲＯ ： 差分ΔＲＲＯ
ＳＢ ： 静アンバランス
α ： 定数
β ： 定数
とする。 In the estimation method, it is preferable that the first relationship is represented by the following equation (1).

However,
ΔRRO: difference ΔRRO
SB: Static imbalance α: Constant β: Constant.

  In the estimation method, it is preferable that in the first step, the first relationship is obtained assuming that the vector of the static imbalance is equal to the combination of the vector of the tread unbalance and the vector of the eccentric component.

ただし、
ＨｓＲＦＶ ： 高速ＲＦＶ
ＬｓＲＦＶ ： 低速ＲＦＶ
ＬｓＲＲＯ ： トレッド部の低速ＲＲＯ
ＳＢ ： 静アンバランス
Ａ ： 定数
Ｂ ： 定数
Ｃ ： 定数
Ｄ ： 定数
とする。 In the estimation method, it is preferable that the second relationship is represented by the following equation (2).

However,
HsRFV: High-speed RFV
LsRFV: Low speed RFV
LsRRO: Low speed RRO of tread
SB: Static imbalance A: Constant B: Constant C: Constant D: Constant.

  In the first step of the present invention, a first relation in which the difference ΔRRO and the static imbalance are associated with each other is acquired for the reference tire, and in the second step, the high-speed RFV, the low-speed RFV, and the low-speed tread portion of the reference tire are obtained. A second relationship in which the RRO is associated with the difference ΔRRO is obtained. In the third step, the low-speed RFV, the low-speed RRO, and the static imbalance are measured for the tire to be inspected. Here, as the “reference tire” for the “inspection tire”, a tire of the same type is applied. "Same type tire" means a group of tires manufactured using substantially the same molding machine and vulcanizing mold and having the same size, the same internal structure, and the same tread pattern. It is considered to have properties.

  In the fourth step, the static imbalance of the inspected tire measured in the third step is applied to the first relation obtained in the reference tire. Thereby, the difference ΔRRO for the tire to be inspected is estimated. Further, in the fifth step, the low-speed RFV of the inspected tire measured in the third step, the low-speed RRO of the tread portion, and the difference ΔRRO of the inspected tire estimated in the fourth step are applied to the second relationship. Is done. Accordingly, the high-speed RFV can be easily and accurately estimated without rotating the inspected tire at a high speed and measuring the high-speed RRO or the like.

It is a sectional view of the pneumatic tire of the present invention. It is a flowchart which shows the manufacturing process of a pneumatic tire. It is a flowchart explaining the procedure of the estimation method of the high speed uniformity of this invention. 4 is a flowchart showing a detailed procedure of a first step in FIG. 3. It is a side view of a pneumatic tire which shows a vector which acts on a rotating pneumatic tire. 4 is a flowchart illustrating a detailed procedure of a second step in FIG. 3. It is sectional drawing of a vulcanization metal mold. 9 is a graph showing a correlation between a tread unbalance and a primary component of a difference ΔRRO for a reference tire. 9 is a graph showing a correlation between a tread unbalance and a primary component of a difference ΔRRO for a reference tire having a different size from that of FIG. 8. FIG. 10 is a graph showing the correlation between the tread unbalance and the primary component of the difference ΔRRO for reference tires of different sizes from those of FIGS. 9 is a graph showing a correlation between an estimated value of a high-speed RFV and an actually measured value of a high-speed RFV for a measured tire of the same type as the reference tire of FIG. 8. 10 is a graph showing a correlation between an estimated value of a high-speed RFV and an actually measured value of a high-speed RFV for a tire to be measured of the same type as the reference tire of FIG. 9. 11 is a graph showing a correlation between an estimated value of a high-speed RFV and an actually measured value of a high-speed RFV for a tire to be measured of the same type as the reference tire of FIG. 10.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In the present invention, the high-speed uniformity of the tire is estimated, and the shipping management of the tire is performed based on the estimated value. In this embodiment, a high-speed RFV is estimated as the high-speed uniformity. Then, a tire having a standard whose estimated high-speed uniformity is smaller than a predetermined threshold value is shipped without causing a vibration problem. On the other hand, non-standard tires having a high speed uniformity larger than a predetermined threshold value are buffed or discarded.

  In the present embodiment, the tire is, for example, a pneumatic radial tire for a passenger car (hereinafter, simply referred to as a “pneumatic tire”) in which vibration is likely to be a problem. As shown in FIG. 1, a pneumatic tire 1 includes a carcass 6 extending from a tread portion 2 to a bead core 5 of a bead portion 4 via a sidewall portion 3, a radially outer portion of the carcass 6 and an inner portion of the tread portion 2. And a belt layer 7 disposed on the other side.

  The tire for which high-speed RFV is estimated in the present invention is not limited to the pneumatic tire 1 described above. For example, the present invention is also applicable to an airless tire including a cylindrical tread ring having a ground contact surface, a hub fixed to an axle, and spokes connecting the tread ring and the hub.

  FIG. 2 shows a manufacturing process of the pneumatic tire 1. In the present embodiment, first, a large number of raw tires for tires of the same type are molded using a plurality of substantially identical tire molding machines K1, K2,. Each of the tire forming machines K1, K2,... Is configured to include, for example, a cylindrical forming drum and an applicator for supplying various tire components to the drum (not shown). The green tire is formed by attaching necessary members such as an unvulcanized rubber material and a ply to the forming drum and shaping them into a toroidal shape. Also, each of the tire forming machines K1, K2,... Is made with substantially the same specifications in order to make the same green tire. The molded green tire is vulcanized and molded as the same type of the pneumatic tire 1 by using a plurality of substantially identical vulcanization molds M1, M2.

  Here, the “same type” pneumatic tires mean a group of tires manufactured using substantially the same molding machine and vulcanization mold, and having the same size, the same internal structure, and the same tread pattern. I do. For example, the tire groups manufactured in different manufacturing lots are pneumatic tires of the same type. Such tires of the same type have substantially the same specifications and characteristics except for slight variations in manufacturing.

  FIG. 3 shows an example of a procedure of a method of estimating a high-speed RFV as a high-speed uniformity of the present embodiment. The estimation method according to the present embodiment includes the following first step (S1) to fifth step (S5). Among them, the first step (S1) and the second step (S2) are processing applied to a plurality of reference tires.

  As the “reference tire”, a pneumatic tire of the same type as the tire to be inspected for which the high-speed RFV is estimated by the estimation method of the present invention is applied. “Difference ΔRRO” is the difference between the high-speed RRO and the low-speed RRO of the tread portion 2.

  In the first step (S1), for the reference tire, a first relationship in which the difference ΔRRO and the static imbalance are associated is acquired.

  In the second step (S2), for the reference tire, a second relationship in which the high-speed RFV, the low-speed RFV, the low-speed RRO of the tread portion, and the difference ΔRRO are associated is acquired. With the above processing, preparation for estimating the high-speed RFV of the tire to be inspected is completed.

  The third step (S3) to the fifth step (S5) are processing in which high-speed RFV is applied to an unknown tire to be inspected. In the third step (S3), the low-speed RFV, the low-speed RRO of the tread portion, and the static imbalance are measured for the tire to be inspected. Since it is not necessary to rotate the tire to be inspected at high speed, these measurements can be easily and quickly performed using an inexpensive general-purpose uniformity measuring device.

  Next, in the fourth step (S4), the static imbalance of the tire to be inspected measured in the third step (S3) is applied to the first relationship obtained in the first step (S1), and The difference ΔRRO is estimated.

  Then, in the fifth step (S5), the second relationship acquired in the second step (S2) includes the low-speed RFV measured in the third step (S3), the low-speed RRO of the tread portion, and the fourth step ( The difference ΔRRO estimated in S4) is applied. Thus, the high-speed RFV can be easily and accurately estimated without measuring the high-speed RRO or the like by rotating the inspected tire at a high speed using the dedicated uniformity measuring device.

  The third step (S3) to the fifth step (S5) are repeated until the inspection is completed for all the tires to be inspected (N in S6). When the inspection has been completed for all the tires to be inspected (Y in S6), the process ends.

  In the first relationship, the difference ΔRRO and the static imbalance are associated with each other. The physical quantity associated with the first relationship may be the measured difference ΔRRO and the static imbalance itself, and may be an arbitrary order component (nth component: n is a natural number) of the measured difference ΔRRO and the static imbalance. There may be.

  Similarly, in the second relationship, the high-speed RFV, the low-speed RFV, the low-speed RRO of the tread portion, and the difference ΔRRO are associated with each other. The physical quantities associated with this second relationship may be the measured high speed RFV, low speed RFV, low speed RRO of the tread, and the difference ΔRRO itself, and the high speed RFV, low speed RFV, the low speed RRO of the tread, And an arbitrary order component (nth order component: n is a natural number) of the difference ΔRRO.

  Hereinafter, the present embodiment will be described on the assumption that the first relation and the second relation are obtained with the primary components of the respective physical quantities, and the high-speed uniformity is estimated.

  FIG. 4 shows an example of a detailed procedure of the first step (S1). In the first step (S1), first, the high-speed RRO and low-speed RRO of the tread portion 2 for the reference tire and the primary component of the static imbalance are measured (S11).

  “High-speed RRO” is a radial runout (radial variation) of the tread portion 2 of the pneumatic tire 1 running at a sufficiently high speed (for example, 100 km / h or more) at which a centrifugal force can act. “Low-speed RRO” is a radial deflection (diameter variation) of the tread portion 2 of the pneumatic tire 1 that runs at a sufficiently low speed (for example, 10 km / h or less) at which no centrifugal force acts. Each RRO is measured for one rotation of the tire using a well-known uniformity measuring device (not shown) or the like. Each RRO is obtained as a vector quantity having a magnitude and a phase angle. The phase angle is an angle from a reference position set at an arbitrary position on the tire. For example, the identification tool 8 shown in FIG. 1 is arranged at the reference position. The identification tool 8 is attached, for example, to the outer surface of the tire. As the identification tool 8, for example, a label on which an identification code such as a two-dimensional barcode is printed is preferably used.

  "Static imbalance" is a mass imbalance where the tires are not statically balanced. The static imbalance is, for example, a method in which a tire is mounted on a well-known imbalance measuring device (not shown), and a vector amount having an unbalance amount and a phase angle which is an angle between the peak position and the reference position is set as a static amount. can get.

  In the step (S11), the number of reference tires necessary for accurately obtaining the first relation is measured. In order to enhance the reliability of the data, the number of reference tires measured in the step (S11) is, for example, at least 10 or more, preferably 50 or more, and more preferably about 100.

  Next, the primary component of the difference ΔRRO of each reference tire is calculated from the high speed RRO and the low speed RRO of the tread portion 2 measured in the step (S11) (S12). The difference ΔRRO is obtained as a vector quantity having a magnitude and a phase angle.

  The primary component of the difference ΔRRO is obtained by calculating the difference ΔRRO between the high-speed RRO and the low-speed RRO, and analyzing the difference ΔRRO by FFT (Fast Fourier Transform). The primary component of the difference ΔRRO can also be obtained by calculating the difference between the primary component of the high-speed RRO and the primary component of the low-speed RRO. The difference calculation of the RRO and the extraction of the primary component are performed, for example, by numerical analysis using a computer or the like.

ただし、
ΔＲＲＯ ： 差分ΔＲＲＯ
ＳＢ ： 静アンバランス
α ： 定数
β ： 偏心成分定数
とする。 Thereafter, the primary component of the difference ΔRRO calculated in the step (S12) is associated with the primary component of the static imbalance measured in the step (S11), and a first relationship is obtained (S13). As a result of intensive studies, the inventors have derived that the first relationship represented by the equation (1) exists between the first-order component of the difference ΔRRO and the first-order component of the static imbalance. Was.

However,
ΔRRO: difference ΔRRO
SB: Static imbalance α: Constant β: Eccentric component constant

Note that the vector of the static imbalance can be expressed by the following equation (1 ′) using a complex plane.

  By applying the primary component of the difference ΔRRO calculated in the step (12) and the primary component of the static imbalance measured in the step (S11) to the equation (1), and performing a vector regression analysis, The constant α and the eccentric component constant β are calculated.

FIG. 5 shows vectors acting on the rotating pneumatic tire 1. The vector acting on the rotating pneumatic tire 1 includes a vector of the tread unbalance TI, a vector of the static unbalance, and a vector of the eccentric component constant β. As a result of the research, the inventors have considered that the vector of the static imbalance is a combination of the vector of the tread unbalance TI and the vector of the eccentric component constant β as shown in FIG. 2) was derived.

Further, the inventors believe that the difference ΔRRO largely contributes to the bulging of the weight imbalance portion of the tread portion 2 due to the centrifugal force, and thus the tread angle represented by the following equation (1-3). A relationship between the balance TI and the difference ΔRRO was assumed.

  From the above equations (1-2) and (1-3), the above equation (1) representing the first relationship between the primary component of the difference ΔRRO and the primary component of the static imbalance is calculated.

  Then, the primary component of the static imbalance measured in the step (S11) and the primary component of the difference ΔRRO calculated in the step (S12) are applied to the equation (1), and a vector regression analysis is performed. Thus, the constants α and β are calculated. As a result, a first relationship in which the primary component of the difference ΔRRO and the primary component of the static imbalance are associated is obtained.

  FIG. 6 shows an example of a detailed procedure of the second step (S2). In the second step (S2), first, the primary component of the high-speed RFV, the primary component of the low-speed RFV, and the primary component of the low-speed RRO of the tread portion of the tread portion 2 are measured (S21).

  “High-speed RFV” is a variation in a radial force acting on the rotation axis of the pneumatic tire 1 running at a sufficiently high speed (for example, 100 km / h or more) at which a centrifugal force can act. The high-speed RFV is measured for one rotation of the tire using a dedicated high-speed uniformity measuring device (not shown). Then, in the same manner as described above, the measured high-speed RFV waveform data is subjected to order analysis, and a required high-speed RFV order component is calculated. Each order component of the high-speed RFV is obtained as a vector quantity having a magnitude and a phase angle.

  As described above, the measurement of the high-speed RFV requires more expensive equipment and more time than the low-speed RFV. However, in the present invention, the measurement of the high-speed RFV is performed when first obtaining the second relation for the reference tire. Then, the acquired second relationship is applied to the measured tires of the same type. Therefore, in the implementation of all the steps of the present invention, the time required for measuring the high-speed RFV is short.

  “Low-speed RFV” is a variation in a radial force acting on the rotation axis of the pneumatic tire 1 running at a sufficiently low speed (for example, 10 km / h or less) at which no centrifugal force acts. This low-speed RFV is measured for one round of the tire using a general-purpose uniformity measuring device (not shown) or the like. The order of the measured data of the low-speed RFV is analyzed using a computer or the like, and the order component of the low-speed RFV necessary for setting the estimation formula is calculated. Each order component of the low-speed RFV is obtained as a vector quantity having a magnitude and a phase angle.

  Next, the primary component of the high-speed RFV, the primary component of the low-speed RFV, the primary component of the low-speed RRO of the tread portion, which is measured in the step (S21), and the difference ΔRRO calculated by the above-mentioned step (S12) From the next component, the high-speed RFV, the low-speed RFV, the low-speed RRO of the tread portion, and the difference ΔRRO are associated. Thereby, the second relationship is obtained (S22). The primary component of the high-speed RFV, the primary component of the low-speed RFV, the primary component of the low-speed RRO of the tread portion, and the primary component of the difference ΔRRO for the reference tire are associated here.

ただし、
ＨｓＲＦＶ ： 高速ＲＦＶ
ＬｓＲＦＶ ： 低速ＲＦＶ
ＬｓＲＲＯ ： トレッド部の低速ＲＲＯ
Ａ ： 定数
Ｂ ： 定数
Ｃ ： 定数
Ｄ ： 定数
とする。 As a result of further research, the inventors have considered that the second relationship between the first-order component of the high-speed RFV, the first-order component of the low-speed RFV, and the first-order component of the difference ΔRRO can be approximated by the following equation (2). .

However,
HsRFV: High-speed RFV
LsRFV: Low speed RFV
LsRRO: Low speed RRO of tread
A: constant B: constant C: constant D: constant.

  The first relation and the second relation thus obtained are relations for the reference tire. However, as described above, the reference tire and the inspected tire for which the high-speed RFV is estimated in the present invention are tires of the same type having substantially the same specifications and characteristics. Therefore, the first relation and the second relation can be extended and applied to a tire to be inspected having the same uniformity characteristics as the reference tire.

  That is, first, in the fourth step (S4) shown in FIG. 3, the primary component of the static imbalance measured in the third step (S3) is applied to the equations (1) to (1-3). , The primary component of the difference ΔRRO of the inspected tire is estimated. By using the equations (1) to (1-3), the primary component of the difference ΔRRO can be estimated without measuring the high-speed RRO for the tire to be inspected.

  Further, in the fifth step (S5), the primary component of the low-speed RFV measured in the third step (S3) and the primary component of the low-speed RRO of the tread portion are estimated in the fourth step (S4). The primary component of the difference ΔRRO is applied to equation (2), and the primary component of the high-speed RFV of the tire to be inspected is estimated. By using equation (2), the high-speed RFV can be estimated without measuring the tire to be inspected.

  By the way, as shown in FIG. 7, the vulcanizing mold M has a plurality of split molds Ma, Mb... Having a tire molding surface 10 inside, and a molding cavity formed by closing the split molds Ma, Mb. And a balloon-shaped bladder 11 which expands and contracts in the interior and presses the raw tire against the tire molding surface. The split dies Ma, Mb... Are arranged so as to be able to move toward and away from each other by a press (not shown). However, the processing accuracy of the split dies Ma, Mb. There is variation. In addition, the processing accuracy of the bladder 11, the degree of expansion thereof, and the like also have minute variations for each vulcanizing mold. These variations give a slight difference to the flow of unvulcanized rubber and the distortion remaining in each part of the tire during vulcanization of the green tire, and also affect the uniformity.

  In view of such a situation, it is desirable that the first relation and the second relation for estimating the high-speed uniformity be set for each of the vulcanizing dies M1, M2,. By setting the first relation and the second relation for each vulcanizing mold, it is possible to prevent the estimation accuracy of the high-speed uniformity from deteriorating due to the above-described inherent factor (that is, the vulcanizing factor) depending on the vulcanizing mold. Can be prevented. Therefore, the high-speed uniformity can be more accurately estimated. The first relation and the second relation for each vulcanizing mold are set in the same manner as described above by performing the above-described steps S1 and S2 for each pneumatic tire 1 of the same type manufactured by each vulcanizing mold. it can.

  Further, as shown in FIG. 1, the pneumatic tire 1 is preferably provided with an identification tool 8 for specifying a vulcanizing mold M or the like that has formed the tire.

  The label is made of a heat-resistant material that is not deformed by heat during vulcanization and that can leave the barcode without disappearing. Thus, in executing the first to third steps, the bar code of the identification tool 8 attached to the pneumatic tire 1 is read, and the pneumatic tire 1 is vulcanized by any vulcanizing mold. Can be easily specified.

  It is desirable that the discriminating tool 8 is preferably attached to a raw tire before vulcanization. For example, as shown in FIG. 1, it is desirable that the sheet-like sidewall rubber 3G is pasted so as to indicate the position of the joint portion where the side wall rubber 3G is overlapped. This is because the joint portion of the sidewall rubber 3G easily causes a mass imbalance, and is likely to affect the uniformity of the tire.

  The joint portion of the tread rubber 2G also tends to cause a mass imbalance, and is likely to affect the uniformity of the tire. Therefore, it is desirable that the tread rubber 2G be adhered so that the joint portion of the tread rubber 2G always has the same relative positional relationship with the joint portion of the sidewall rubber 3G.

  Furthermore, in the vulcanization step, it is desirable to position and position the green tire in the vulcanization mold M so that the position of the identification tool 8 always has the same relative positional relationship with the vulcanization mold M.

  The pneumatic tire 1 is vulcanized after the joint portion of the tread rubber 2G and the side wall rubber 3G is always positioned at a fixed phase with respect to the vulcanization mold M, thereby causing vulcanization factors and production. It is possible to always meet the tire unbalance factor in the same state. Therefore, the variation of the pneumatic tire 1 after vulcanization is reduced, and the first relationship and the second relationship can be set more accurately. In the measuring step, the label can be used as a reference position in the tire circumferential direction.

  The eccentric component constant β represented by the above equations (1) and (1-3) is greatly affected by the roundness, operation accuracy (eccentricity), and the like of a tire building drum for forming a green tire. Therefore, in order to fix the influence of the roundness and the operation accuracy (eccentricity) of the tire building drum, the first relationship and the second relationship are desirably set for each tire building drum. As a method for specifying the tire building drum, the discriminator 8 including the label displaying the barcode as described above is effective.

  In addition, environmental temperature, humidity, equipment status, and / or accuracy of the uniformity measuring device in the tire manufacturing factory are fluctuation factors that change daily. In other words, these variation factors may cause changes in the tire finish or RFV measurement error. Therefore, it is desirable to include a step of reviewing the first relationship and the second relationship in order to remove the deterioration of the estimation accuracy of the high-speed uniformity based on these fluctuation factors and keep the estimation accuracy always high. For example, a monitoring span of several days or weeks may be set in advance, and the first relationship and the second relationship may be reviewed at this timing.

  As described above, the method for estimating the high-speed uniformity of a tire according to the present invention has been described in detail. However, the present invention is not limited to the above-described specific embodiments, but may be implemented in various modes.

  As reference tires, a high-speed RRO, a low-speed RRO, a static unbalance, a primary component of a high-speed RFV, and a primary component of a low-speed RFV were measured for 15 pneumatic tires of three sizes. The size is 195 / 65R15, 225 / 60R18, 235 / 55R20. Each tire has the same internal structure and the same tread pattern for each size, and is manufactured using the same forming drum and the same vulcanizing mold.

  8 to 10 show the difference ΔRRO obtained from the measured high-speed RRO, low-speed RRO, and static unbalance primary components based on the above equations (1), (1-2), and (1-3). The relationship between the primary component and the tread unbalance TI is shown. 8 shows the relationship for the size 195 / 65R15, FIG. 9 shows the relationship for the size 225 / 60R18, and FIG. 10 shows the relationship for the size 235 / 55R20.

  As is clear from FIGS. 8 to 10, a very high correlation was obtained between the primary component of the difference ΔRRO and the tread imbalance TI. Therefore, it was confirmed that the first relationship was accurately acquired based on the above equations (1), (1-2), and (1-3).

  FIGS. 11 to 13 show the relationship between the estimated value of the high-speed RFV of the measured tire estimated according to the procedures of FIGS. 3, 4 and 6, and the actual measured value of the high-speed RFV measured using the high-speed uniformity measuring device. Is shown. The tires to be measured were of the same type as the reference tires measured in FIGS. 8 to 10, and the high-speed RFV was estimated and measured for 15 pneumatic tires of each size. 11 shows the relationship for the size 195 / 65R15, FIG. 12 shows the relationship for the size 225 / 60R18, and FIG. 13 shows the relationship for the size 235 / 55R20.

  As is clear from FIGS. 11 to 13, a very high correlation was obtained between the estimated value of the high-speed RFV and the measured value of the high-speed RFV. In particular, a remarkably high correlation was obtained in the size 235 / 55R20 having a low flatness and a high belt layer tension. Therefore, it was confirmed that the high-speed RFV of the pneumatic tire can be accurately estimated by the estimation method of the present invention.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part S1 1st process S2 2nd process S3 3rd process S4 4th process S5 5th process

Claims (8)

A method for estimating high speed uniformity of a tire, comprising:
A first step of acquiring a first relationship in which a difference ΔRRO, which is a difference between a high-speed RRO and a low-speed RRO of a tread portion, and a static imbalance are associated with each other;
A second step of acquiring a second relationship in which the reference tire is associated with a high-speed RFV, a low-speed RFV, the low-speed RRO of the tread portion, and the difference ΔRRO;
A third step of measuring a low-speed RFV, a low-speed RRO of a tread portion, and a static imbalance for a test tire of the same type as the reference tire and whose high-speed RFV is unknown;
A fourth step of applying the static imbalance measured in the third step to the first relation, and estimating a difference ΔRRO of the tire to be inspected;
as well as,
The low-speed RFV measured in the third step, the low-speed RRO, and the difference ΔRRO estimated in the fourth step are applied to the second relation to estimate the high-speed RFV of the tire to be inspected. A high-speed uniformity estimation method for a tire, comprising:   The method for estimating a high-speed uniformity of a tire according to claim 1, wherein the first step includes a step of measuring the high-speed RRO, the low-speed RRO, and the static imbalance of the tread portion with respect to the reference tire.   The tire high-speed uniformity estimation method according to claim 1, wherein the second step includes a step of measuring the high-speed RFV, the low-speed RFV, and the low-speed RRO of the tread portion for the reference tire. .   The method for estimating a high-speed uniformity of a tire according to any one of claims 1 to 3, wherein the first relationship is such that an nth-order component of the difference ΔRRO is associated with an nth-order component of the static imbalance. Here, n is a natural number.   The second relationship is such that an n-th component of the high-speed RFV, an n-th component of the low-speed RFV, an n-th component of the low-speed RRO of the tread portion, and an n-th component of the difference ΔRRO are associated with each other. 5. The method for estimating high-speed uniformity of a tire according to any one of 1 to 4. Here, n is a natural number. The tire high-speed uniformity estimation method according to any one of claims 1 to 5, wherein the first relation is represented by the following equation (1).

However,
ΔRRO: difference ΔRRO
SB: Static imbalance α: Constant β: Constant.   The first relationship is obtained in the first step, assuming that the static unbalance vector is equal to a combination of a tread unbalance vector and an eccentric component vector. Method for estimating the high-speed uniformity of tires. The method for estimating high-speed uniformity of a tire according to any one of claims 1 to 7, wherein the second relation is represented by the following equation (2).

However,
HsRFV: High-speed RFV
LsRFV: Low speed RFV
LsRRO: Low speed RRO of tread
A: constant B: constant C: constant D: constant.

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