JP4528083B2 - Tire uniformity measuring method and tire uniformity measuring apparatus used therefor - Google Patents

Description

  The present invention relates to a tire uniformity measuring method for identifying an AVV (angular velocity variation) characteristic used as a substitute characteristic of a TFV (tangential force variation) of a tire, and in particular, due to an error of a measuring instrument and the like. Relates to a tire AVV characteristic waveform that can be identified with high accuracy by eliminating tire axis AVV measurement errors and tire axis AVV measurement errors that appear independently.

Conventionally, a tire is mounted on a rim rotatable around a tire rotation axis, and the tire is rotated while pressing the tire with a predetermined load against a peripheral surface of a load drum that rotates around an axis parallel to the tire rotation axis. A tire AVV characteristic waveform is identified based on the obtained AVV (angular velocity fluctuation) waveform (see, for example, Patent Document 1). And the method of using the obtained AVV waveform as it is as the tire AVV characteristic waveform waveform is the simplest, and this method is generally performed.
International Publication No. 03/034023 Pamphlet

  However, in this case, the AVV waveform obtained by the measurement does not represent the true tire AVV characteristic waveform, and the tire axis AVV measurement error and the drum axis appearing independently of the tire due to an error of the measuring instrument or the like. In addition to the AVV measurement error, the influence of the angular velocity fluctuation of the load drum accelerated / decelerated by the tire AVV is superimposed, and the inventor cannot ignore these effects in order to identify the tire AVV characteristic waveform with high accuracy. I found out.

  The present invention has been made in view of such problems. In addition to a tire axis AVV measurement error and a tire axis AVV measurement error, the present invention eliminates errors due to fluctuations in the angular velocity of the load drum, and provides high-precision tire AVV characteristics. It is an object of the present invention to provide a tire uniformity measuring method and measuring apparatus capable of identifying a waveform.

ただし、
X：タイヤ位相範囲ΣにおけるタイヤＡＶＶ特性波形
F：タイヤ位相範囲Σにおけるタイヤ軸計測波形
K：ドラム位相範囲Ψにおけるドラム軸計測波形
H：ドラム軸ＡＶＶ誤差波形
R：タイヤ／ドラム半径比（負荷ドラム半径に対するタイヤ転がり半径の比）
G：タイヤ軸ＡＶＶ誤差波形 <1> rotates the tire mounted on the rim while pressing the tire around the axis of rotation of the load drum provided at a predetermined rotational speed against a circumferential surface of a load drum rotatably provided around the axis of rotation. This is based on the tire axis AVV measurement waveform obtained by measuring the tire AVV (angular speed fluctuation) and the drum axis AVV measurement waveform obtained by measuring the angular speed fluctuation of the loaded drum around the drum rotation axis. In a uniformity measurement method for identifying a tire AVV characteristic waveform representing a tire-specific angular velocity fluctuation characteristic,
F is the tire axis measurement waveform in the tire phase range Σ for one tire lap, and K is the drum axis measurement waveform in the drum phase range Ψ corresponding to the tire phase range Σ as a contact range between the peripheral surfaces. These tires F, K, tire shaft AVV error waveform G and drum shaft AVV error waveform H, which are identified in advance and appear independently of the tire, are substituted into equation (1), and the tire AVV characteristics are obtained. This is a tire uniformity measurement method for identifying the waveform X.

However,
X: Tire AVV characteristic waveform in the tire phase range Σ
F: Tire axis measurement waveform in the tire phase range Σ
K: Drum axis measurement waveform in drum phase range Ψ
H: Drum axis AVV error waveform
R: Tire / drum radius ratio (ratio of tire rolling radius to load drum radius)
G: Tire axis AVV error waveform

ただし、
X₁：基準タイヤのタイヤＡＶＶ特性波形
F₁：基準タイヤ装着時のタイヤ軸ＡＶＶ計測波形
K₁：基準タイヤ装着時のドラム軸ＡＶＶ計測波形
H：前記ドラム軸ＡＶＶ誤差波形
R₁：基準タイヤに対するタイヤ／ドラム半径比
G：タイヤ軸ＡＶＶ誤差波形 In <2>, in identifying the tire axis AVV error waveform G in the formula (1) in <1>, a reference tire having a known tire AVV characteristic waveform is attached to the rim, and the tire is rotated one or more times. The tire uniform for obtaining the tire axis AVV error waveform G using the equation (2) from the tire axis measurement waveform F ₁ and the drum axis measurement waveform K ₁ obtained as described above, with the tire AVV characteristic waveform of the reference tire as X _1. This is a method for measuring Mitty.

However,
X ₁ : Tire AVV characteristic waveform of the reference tire
F ₁ : Tire axis AVV measurement waveform when the reference tire is installed
K ₁ : Drum axis AVV measurement waveform when the reference tire is installed
H: Drum axis AVV error waveform
R ₁ : Tire / drum radius ratio relative to the reference tire
G: Tire axis AVV error waveform

  <3> is a method in which a tire is mounted on a rim at a plurality of mounting positions that are different from each other in phase with the rim, and the tire is based on the uniformity measurement method according to claim 2 for each mounting position. This is a tire uniformity measurement method for obtaining an axis AVV error waveform, averaging the tire axis AVV error waveform obtained corresponding to each mounting position, and identifying the tire axis AVV error waveform of the rim.

  <4> is any one of <1> to <3>, and in identifying the drum axis AVV error waveform H in the formula (1) and / or (2), N is an integer of 2 or more, and the tire is (2π / N) contact position relationship between N load drums and tires obtained by rotating by (2π / N) radians or by rotating N times by randomly selected angle and contacting the load drum For each of the above, the tire is rotated against the load drum at a predetermined rotation speed while rotating for at least one rotation of the load drum, and the N drum shaft measurement waveforms obtained at this time are averaged by matching the phase of the load drum This is a tire uniformity measurement method in which the averaged waveform is the drum axis AVV error waveform H.

ただし、
X₁：タイヤＡＶＶ特性波形
F(i)：i番目のタイヤ装着位置に対応するタイヤ軸計測波形
K(i)：i番目のタイヤ装着位置に対応するドラム軸計測波形
H：ドラム軸ＡＶＶ誤差波形
R₁：基準タイヤに対するタイヤ／ドラム半径比 <5>, in any one of <2> to <4>, in Formula (2), upon identifying a tire AVV characteristic waveform X ₁ reference tire, as two or more integer M, the rim, the rim The reference tires are mounted at M mounting positions whose phases are different from each other by (2π / M) radians, or at M mounting positions that are randomly selected at different angles. On the other hand, the tire AVV characteristic waveform of the reference tire is obtained from the tire axis measurement waveform F (i) and the drum axis measurement waveform K (i) obtained by rotating the tire one or more times using the equation (3). This is a method for measuring tire uniformity.

However,
X ₁ : Tire AVV characteristic waveform
F (i): Tire axis measurement waveform corresponding to the i-th tire mounting position
K (i): Drum axis measurement waveform corresponding to the i-th tire mounting position
H: Drum axis AVV error waveform
R ₁ : Tire / drum radius ratio relative to the reference tire

<6> is a tire uniformity measuring device used in the tire uniformity measuring method according to any one of <1> to <5>,
Tire rotating device for rotating a rim on which a tire is mounted, the load drum, each encoder for detecting the rotation angle position of the tire and the load drum, and the angular velocity of the tire and the load drum based on signals from these encoders Each angular velocity fluctuation measuring device for obtaining fluctuations, and an AVV control device for calculating the tire AVV characteristic waveform based on signals from these angular velocity fluctuation measuring devices,
The AVV control device includes a tire type input unit for inputting a tire type to be measured from the outside, a rim ID input unit for inputting an identification code of a rim used for measurement from the outside, and parameters used for calculating a tire AVV characteristic waveform. A parameter storage unit for storing, and a central control unit for calculating the tire AVV characteristic waveform,
The parameter storage unit stores at least the drum axis AVV error waveform, a tire / drum radius ratio for each tire type, and a tire axis AVV error waveform for each rim ID,
The central control unit includes the drum axis AVV error waveform, the tire / drum radius ratio corresponding to the tire type input to the tire type input unit, and the tire axis AVV corresponding to the rim ID input to the rim ID input unit. The error waveform is read from the parameter storage unit, and the tire axis AVV measurement waveform is created based on the signal from the tire shaft angular velocity fluctuation measuring device, and also based on the signal from the drum shaft angular velocity fluctuation measuring device. The drum axis AVV measurement waveform is created, and based on these measurement waveform, the tire / drum radius ratio, the tire axis AVV error waveform, and the drum axis AVV error waveform read from the parameter storage unit, the tire AVV characteristics are obtained. A tire uniformity measuring apparatus configured to perform processing for identifying a waveform.

  According to the invention <1>, the tire AVV characteristic waveform X is identified based on the formula (1) using the tire axis AVV error waveform G and the drum axis AVV error waveform H prepared in advance. Therefore, the AVV measurement error component around the tire shaft and the drum shaft is excluded, and the influence due to the change in the rotational speed of the load drum accelerated / decelerated by the tire AVV characteristics is excluded as K / R in the equation (1). The tire specific AVV can be identified with high accuracy, and the tire axis AVV error waveform G and the drum axis AVV error waveform H are prepared in advance as data, so that the identification is efficiently performed. be able to.

According to the invention <2>, when identifying the tire axis AVV error waveform G in the equation (1), a reference tire having a known tire AVV characteristic waveform is attached to the rim, and the tire is rotated one or more times. The tire axis AVV error waveform G is obtained from the tire axis measurement waveform F ₁ and the drum axis measurement waveform K ₁ obtained as described above, using the tire AVV characteristic waveform of the reference tire as X ₁ and using the equation (2). The tire axis AVV error waveform is obtained based on the tire AVV characteristic waveform of the reference tire obtained in the above and the drum axis AVV error waveform accurately obtained as described later, and the tire axis AVV error waveform is obtained with high accuracy. Can be identified.

  According to the invention <3>, the tire is mounted on the rim at a plurality of mounting positions whose phases with the rim are different from each other, and the uniformity measurement method according to <2> is applied to each mounting position. The tire axis AVV error waveform is obtained based on this, the tire axis AVV error waveform obtained corresponding to each mounting position is averaged, and identified as the tire axis AVV error waveform of the rim. The influence of one measurement error can be suppressed, and the tire AVV characteristic waveform can be identified with higher accuracy.

  According to the invention <4>, N is an integer of 2 or more and the tire is rotated by (2π / N) radians while the tire is mounted on the rim, or is rotated N times by a randomly selected angle. The load drum 1 while pressing the tire against the load drum at a predetermined rotational speed with respect to each of the N contact positions of the load drum and the tire obtained when they are brought into contact with the fixed load drum The N drum axis measurement waveforms obtained at this time are averaged by matching the phase of the load drum, and the averaged waveform is used as the drum axis AVV error waveform H. Therefore, the drum axis AVV measurement waveform Among them, the components caused by the tire rim assembly composed of the tire and the rim can be canceled by canceling each other in different phases, and only the remaining components are extracted and this is measured when measuring the drum axis AVV. Error That is, the drum axis AVV error waveform H can be identified with high accuracy.

According to the invention of <5>, M is an integer equal to or greater than 2, and the rim has M mounting positions whose phases from the rim are different from each other by (2π / M) radians, or at randomly selected angles. The tire tire measurement waveform F (i) and the drum axle measurement waveform obtained by attaching the reference tire at M attachment positions with different positions and rotating the tire one or more times with respect to each attachment position i. Since the tire AVV characteristic waveform of the reference tire is obtained from K (i) using the equation (3), the averaging operation represented by the equation (3) can be used for each measurement with respect to the reference tire phase. The tire axis AVV error waveforms appearing in different phase relationships can be canceled out by canceling each other, and only the tire AVV characteristic waveform of the reference tire can be extracted as the remaining waveform. In measurement, load Of the effect of angular speed variation, in the formula (3), it can be so eliminated as (K (i) -H) / R 1, those identification of tires AVV characteristic waveform of the reference tire precision.

  According to the invention of <6>, with the configuration described above, any tire having a size within a predetermined range is used, and any rim selected from a range of IDs prepared in advance is used. Even when a tire is mounted, these sizes and IDs are automatically identified, and the tire axis AVV error waveform and the drum axis AVV error waveform are subtracted from the tire axis AVV measurement waveform with reference to the information. Processing can be performed automatically and with high accuracy.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view showing a basic configuration of a uniformity measuring apparatus for identifying a tire AVV characteristic waveform. The uniformity measuring device 1 includes a tire rotating device 4 that rotates a rim 3 on which a tire 2 is mounted, a load drum 5 that is rotatably provided around a drum rotating shaft 7 parallel to the rotating shaft 6 of the tire 2, tire rotation A tire shaft encoder 8 that detects the rotation angle position of the tire 2 around the shaft 6, a tire shaft angular velocity variation measuring device 9 that measures the angular velocity variation of the tire 2 based on a signal from the encoder 8, and the drum rotation shaft 7. A drum axis encoder 16 that detects the rotation angle position of the load drum 5 around, a drum axis angular speed fluctuation measuring device 17 that measures the angular speed fluctuation of the load drum 5 based on a signal from the encoder 16, and a tire axis angular speed fluctuation An AVV control device 10 for calculating a tire AVV characteristic waveform of the tire 2 based on signals from both the measuring instrument 9 and the drum shaft angular velocity fluctuation measuring instrument 17 is provided. The tire AVV characteristic waveform can be identified by rotating the tire 2 while pressing it against the peripheral surface 5a of the load drum 5 at a predetermined rotation speed, and measuring the angular velocity fluctuations of the tire 2 and the load drum at that time. Has been.

  The uniformity measurement result is displayed on the display device 14 installed at the site and transmitted to the factory central management device 15, and the factory central management device 15 determines the processing for the measurement result.

  Here, the tire shaft angular velocity variation measuring instrument 9 and the drum shaft angular velocity variation measuring instrument 17 convert information relating to the interval between the pulse signals from the encoders 8 and 16 corresponding thereto into analog signals representing the angular velocity variation. An FM demodulator that demodulates the frequency-modulated FM pulse train signal or a frequency deviation measuring instrument such as KAZ-723 (model number) manufactured by Cocoresearch can be used.

  In the figure, 11 is a tire type reading sensor for identifying the tire type from a stamp made on the tire, and 12 is a rim ID reading sensor for reading an identification code attached to the rim 3 for individually identifying each rim. The reading sensor 11 is a device in which these are mounted together. As will be described later, the tire type and rim ID information is necessary for identifying the tire AVV characteristic waveform, but other means such as a computer, Such information can also be obtained by tracing the vulcanized tire and the rim to be used from the initial stage.

  FIG. 2 is a block diagram showing the configuration of the AVV control device 10. The AVV control device 10 includes a tire type input unit 21 for inputting the type of tire to be measured from an external reading sensor 11, and a rim used for measurement. Similarly, a rim ID input unit 21 that inputs the identification code of the tire from the reading sensor 11, a parameter storage unit 23 that stores parameters used to calculate the tire AVV characteristic waveform, and a central control unit 24 that calculates the tire AVV characteristic waveform With

  The parameter storage unit 23 stores at least a tire / drum radius ratio for each tire type, a tire axis AVV error waveform for each rim ID, and an identified drum axis AVV error waveform identified in advance by measurement. The central control unit 24 receives the drum axis AVV error waveform, the tire / drum radius ratio corresponding to the tire type input to the tire type input unit 21, and the rim ID input unit 22 from the parameter storage unit 23. The tire axis AVV error waveform corresponding to the rim ID is read, the tire axis AVV measurement waveform (F) input from the tire axis angular velocity fluctuation measuring instrument 8, and the drum axis AVV measurement waveform input from the drum axis angular speed fluctuation measuring instrument 17. (K) and tire / drum radius ratio, tire axis AVV error waveform, drum axis AVV meter read from parameter storage unit 23 Waveform, and based on the drum shaft AVV error waveform is configured to perform a process of identifying the tire AVV characteristic waveform.

  A method for obtaining a tire AVV characteristic waveform using such an apparatus 1 will be described. FIG. 3 is a process diagram showing processes necessary for obtaining the tire AVV characteristic waveform (X), and these processes are roughly divided into four processes including a preparation process P1 to P3 and a measurement process M. Can do. In the preparation step P1, a drum axis AVV error waveform (H) representing a measurement error of a measuring instrument or the like in the AVV measurement around the drum axis is identified (step P1a), and this is stored in the parameter storage unit 23 (step P1a). In the preparation step P2, for all rims 3 used for uniformity measurement, for each rim ID (j) (j = 1,. The tire axis AVV error waveform (G (j)) caused by the non-uniformity is identified (process P2a), stored in the parameter storage unit 23 (process P2b), and in the preparation process P3, all the measurement targets For each tire type, the load drum 5 at each contact point under the measurement of the tire axis AVV measurement waveform and the drum axis AVV measurement waveform corresponding to each tire type (i) (i = 1,..., I). Vs radius of Tire / drum radius ratio that represents the radius of the ratio of the tire 2 that (R (i)) was measured (step P3a), and stores them in the parameter storage section 23 (step P3b).

In the measurement process M, the rim ID (j = j ₀ ) of the rim used for measurement is input from the process M1, and the tire type (i = i ₀ ) of the tire to be measured is input from the outside in the process M2. At the same time, the tire 2 is mounted on the rim 3, and the uniformity measuring device 1 is used to generate the tire axis AVV measurement waveform (F) from the tire axis angular velocity fluctuation measuring instrument 8, and from the drum axis angular velocity fluctuation measuring instrument 17 to the drum axis. An AVV measurement waveform (K) is input (steps M3a and M3b), and in step M4, the drum axis AVV error waveform (H) and the rim ID of the rim used for measurement (j = j ₀ ) are received from the parameter storage unit 23. The tire axis AVV error waveform (G (j ₀ )) corresponding to, and the tire / drum radius ratio (R (i ₀ )) corresponding to the tire type (i = i ₀ ) of the tire to be measured are read. Parameters, acquired tire axis AVV measurement waveform (F , And the drum shaft AVV measured waveform (K) on the basis, to identify the tire AVV characteristic waveform (X).

  When the tire axis AVV error waveform (G (j)) can ignore the influence of the rim attached to the tire axis, in step P2, the tire axis AVV error waveform is identified as the only numerical value (G) independent of the rim. In this case, the step M1 for inputting the rim ID can be made unnecessary.

  Hereinafter, the process M4 for identifying the tire AVV characteristic waveform (X), the process P1a for identifying the drum axis AVV error waveform (H), and the process P2a for identifying the tire axis AVV error waveform (G (j)) will be described. Details will be described in this order. In order to make the explanation easy to understand, the waveform used in the following description is obtained by extracting only the first harmonic component of the actual waveform, and the circumference of the load drum 5 is three times the circumference of the tire in the pressed state. It was. In the following description, θ, φ, and ψ indicate circumferential angles from a predetermined reference position for the tire 2, the rim 3, and the load drum 5, respectively, corresponding to this order.

First, the process M4 for identifying the tire AVV characteristic waveform (X) will be described in detail based on FIG. 4 and FIG. FIG. 4 is shown to help understand the following description, and points P on the tire corresponding to each other in a state where the tire 2 mounted on the rim 3 and the load drum 5 are in contact with each other. FIG. 8 is a diagram showing the angular position of a point Q on the rim and a point R on the load drum 5 by respective angular coordinates, and in the state shown, the angular position of the point P on the tire 2 is θ = 0 radians, The angular position of the point Q on the rim 3 is φ = φ ₀ radians, and the angular position of the point R on the load drum 5 is ψ = φ ₀ radians.

  FIG. 5A shows a tire axis phase range for three tires obtained by rotating the tire 2 at a predetermined rotational speed while pressing the tire 2 against the load drum 5 using the uniformity measuring apparatus 1 shown in FIG. The tire axis AVV measurement waveform (F) of Θ (θ = 0 to 6π) is shown with the angular velocity of the tire 2 on the vertical axis and the circumferential angular position on the tire on the horizontal axis. The origin was made to correspond to a predetermined angular position on the tire determined to be θ = 0 radians.

FIG. 5B shows the drum axis AVV measurement waveform in the drum axis phase range Ψ (ψ = ψ _{0 to} ψ ₀ + 2π) corresponding to the tire axis phase range Θ, the angular velocity of the load drum 5 as the vertical axis, The drum shaft angle position is shown on the shaft.

FIG. 5C shows the tire axis AVV error waveform (G (j ₀ )) corresponding to the rim ID (j = j ₀ ) of the rim 3 used for the measurement as the circumferential position φ = 0 of the mounted tire 2. This waveform shows one lap (φ = φ _{0 to} φ ₀ + 2π) with the corresponding rim circumferential position φ = φ ₀ as the origin. The vertical axis shows the angular velocity and the horizontal axis shows the tire axis angular position. I showed it.

FIG. 5D shows the drum axis AVV error waveform (H) in the drum axis phase range ψ (ψ = ψ _{0 to} ψ ₀ + 2π) corresponding to the tire axis phase range Θ read from the parameter storage unit 23. The vertical axis represents the angular velocity, and the horizontal axis represents the drum axis angular position.

The tire axis AVV measurement waveform (F) includes not only the tire AVV characteristic waveform (X) unique to the tire 2 but also a tire axis AVV error waveform (G (j ₀ ) due to an AVV measurement error around the tire axis. ), And a drum shaft AVV error waveform (H) due to an AVV measurement error around the drum shaft, etc. are superimposed. In addition, the rotation of the load drum 3 circumscribing the tire 2 is accelerated / decelerated by the AVV of the tire 2. Further, a feedback AVV component (T) generated by feeding back the change in the peripheral speed to the tire 2 and accelerating / decelerating the rotation of the tire 2 is also superimposed.

Therefore, in order to accurately identify the AVV that depends only on the tire, it is necessary to extract only the tire AVV characteristic waveform (X) that does not include the influence of the rim 3 and the load drum 5 from the tire axis AVV measurement waveform (F). For this purpose, the tire axis AVV measurement waveform (F) is subtracted from the tire axis AVV error waveform (G (j ₀ )), the drum axis AVV error waveform (H), and the feedback AVV component (T). It is necessary to obtain the AVV characteristic waveform (X).

  Here, the feedback AVV component (T) is proportional to the drum axis AVV measurement waveform (K), and the gain of the feedback amount from the drum axis AVV measurement waveform has the same peripheral speed between the drum axis and the tire axis. Therefore, the radius of the load drum is divided by the tire radius, and R can be expressed as T = K / R, where R is the tire / drum radius ratio. When the influence of the drum axis AVV error waveform (H) is removed, the gain of the influence is similarly obtained by dividing the radius of the load drum by the tire radius, that is, (1 / R).

Summarizing the above, the equation (1 ′) can be derived.

  Of course, in this calculation, it is necessary to subtract those waveforms in phase with the tire, but this is different from each other on the tire 2, the rim 3, and the load drum 5. This means that the processing is performed so that the phase of the point maintains the correspondence even on the waveforms (F), (G), and (H).

  As described above, the tire AVV characteristic waveform (X) is obtained from the waveforms of FIG. 5A to FIG. 5D based on the equation (1 ′). FIG. The tire AVV characteristic waveform (X) obtained in this way for one round is shown. Similarly, the second tire portion (θ = 2 to 4π) and the third tire portion (θ = 4 to 6π) are also obtained, and the waveforms corresponding to the first to third rounds are obtained. (X) is averaged and identified as a tire AVV characteristic waveform.

  In the case of the above example, three periods of the waveform (X) are averaged to obtain the tire AVV characteristic waveform, but one waveform (X) may be directly used as the tire AVV characteristic waveform without averaging. The digitizing process is not essential in this case. Further, more periods may be averaged. In this case, the measurement error can be reduced by averaging more periods.

Next, the process in step P1a, that is, a method for identifying the drum axis AVV error waveform (H) used to obtain the tire AVV characteristic waveform (X) in the equations (1) and (2) will be described below. . 6 (a) to 6 (h), the tire 2 is mounted on the rim 3, and the tire 2 is fixed to (2π / N) radians (N in the case of illustration) while the phase between the rim 3 and the tire 2 is fixed. = 8, that is, 45 °) for each of the N contact position relationships between the load drum 5 and the tire 2 obtained when each of them rotates and is brought into contact with the fixed load drum 5. Using the uniformity measuring apparatus 1 shown in FIG. 1, the tire 2 is pressed against the load drum 5 while rotating the load drum at least one rotation at a predetermined rotational speed, and the drum axis AVV measurement waveform (K ( δ)) is shown with the drum axis rotation position on the horizontal axis for the drum axis phase range ψ (ψ = ψ _{0 to} ψ ₀ + 2π) corresponding to the tire axis phase range Θ for three tires.

  In addition, the variable δ of the AVV measurement waveform (K (δ)) is set so that the tire phase in the contact position relationship defined as a reference is zero in the contact position relationship between the load drum 5 and the tire 2. It represents the phase of the tire relative to the positional relationship. FIG. 7A to FIG. 7C are diagrams showing examples of the contact position relationship. FIG. 7A shows a reference contact position relationship corresponding to FIG. FIG. 7B is a conceptual diagram showing the relative position of the tire 2 and the load drum 5. FIG. 7B shows the contact position relationship corresponding to FIG. 6B, which is shifted by (2π / 8) radians. (C) is a conceptual diagram showing the contact position relationship corresponding to FIG. 6 (d), which is further shifted by (2π / 4) radians, that is, 90 °.

In the present invention, the drum axis AVV measurement waveform (K (δ)) is averaged, and the averaged waveform is identified as the drum axis AVV error waveform (H). FIG. 6 (i) shows the drum axis AVV error waveform (H) obtained by averaging in this way, and the method for obtaining the above drum axis AVV error waveform (H) can be expressed by equation (4). .

  In this way, the principle of the method of identifying the drum axis AVV error waveform (H) is that the original waveforms are mutually offset by shifting the phases by a predetermined angle and averaging the waveforms, and are added with the same phase. This is based on the fact that only the component, in this case only the drum axis AVV error waveform (H) remains. Here, in order to cancel high-order harmonic components and extract only the drum axis AVV error waveform (H) with high accuracy, it is only necessary to increase N, but the processing time increases in inverse proportion to accuracy. Therefore, N should be determined in consideration of these points.

  In this description, the load drum is averaged over one round, but a plurality of rounds may be averaged. In this case, it is possible to deal with a decrease in accuracy due to measurement variations.

Next, the process in step P2a, that is, a method for identifying the tire axis AVV error waveform (G (j ₀ )) will be described below. FIG. 8A is obtained by using the uniformity measuring apparatus 1 shown in FIG. 1 and having a known tire AVV characteristic waveform and rotating the reference tire 2A at a predetermined rotational speed while pressing it against the load drum 5. The tire axis AVV measurement waveform (F ₁ ) in the phase range Θ for three tire laps with the measured angular velocity on the vertical axis and the horizontal axis corresponding to the position origin of θ = 0 radians on the tire The position in the circumferential direction is taken.

FIG. 8B shows a drum shaft AVV measurement waveform (K ₁ ) in the drum shaft phase range ψ (ψ = ψ _{0 to} ψ ₀ + 2π) corresponding to the tire shaft phase range Θ, with respect to the reference tire 2A, as a load. The angular velocity of the drum 5 is taken on the vertical axis, and the drum shaft angular position is taken on the horizontal axis.

FIG. 8 (c) shows a known tire AVV characteristic waveform (X ₁ ) of the reference tire 2A continuously with the tire axis phase range Θ (θ = 0 to 6π), that is, three tire laps. It is. A method for identifying this will be described later separately.

FIG. 8D shows the load drum 5 in the drum shaft phase range ψ (ψ = ψ _{0 to} ψ ₀ + 2π) (see FIG. 4) corresponding to the tire shaft phase range Θ read from the parameter storage unit 23. The drum axis AVV error waveform (H) is a waveform in which the vertical axis indicates the angular velocity and the horizontal axis indicates the drum axis angular position.

The tire axis AVV error waveform (G (j ₁ )) is, as is clear from the above description, the influence of the drum axis AVV from the tire axis AVV measurement waveform (F) shown in FIG. This can be calculated by subtracting R ₁ as the tire / drum radius ratio relative to the reference tire. It can be expressed as formula (2 ′).

FIG. 8E shows the angular range ψ = ψ _{0 to} ψ ₀ + 2π of the rim 2 corresponding to the tire axial angle range θ = _{0 to} 2π on the first round of the tire, using the formula (2 ′). The tire axis AVV error waveform (G (j ₁ )) is obtained. Then, keep the present invention was determined in the same manner, the angular range of the rim _{2 ψ = ψ 0 + 2π~ψ 0} + 4π, and the angle ranges of the rim _{2 ψ = ψ 0 + 4π~ψ 0} + 6π also The three included waveforms are averaged, and the tire axis AVV error waveform (G (j ₁ )) is identified. FIG. 8F shows this averaged waveform. In this example, the tire shaft AVV error waveform (G (j ₁ )) is averaged over three rim 3 rims, but only one rim 3 lap may be averaged. The tire axis AVV error waveform (G (j ₁ )) may be calculated for a plurality of rounds and averaged, and the number of rounds to be averaged can be appropriately determined according to the required accuracy.

Further, the reference tire 2A is mounted on the rim 3 with the phase changed, and the tire axis AVV error waveform (G (j ₁ )) is obtained based on the equation (2 ′) for each of the mounting positions of different phases. The tire axis AVV error waveform (G (j ₁ )) can also be averaged by calculating the values obtained for these mounting positions. In this case, the dependency on the mounting position is eliminated and the tire axis AVV error is eliminated. The waveform (G (j ₁ )) can be identified with higher accuracy.

Next, a method for identifying the tire AVV characteristic waveform (X ₁ ) of the reference tire 2A used in Expression (5) will be described. 9 (a) to 9 (h) show mounting positions obtained by rotating the rim 3 by (2π / M) radians (M = 8 in the illustrated case, that is, 45 °) with respect to the tire 2. 1 is rotated using the uniformity measuring apparatus 1 shown in FIG. 1 while the tire 2 is pressed against the load drum 5 at a predetermined rotation speed for at least one rotation of the tire, and the tire axis AVV obtained at this time is rotated. From the measured waveform (F (δ1)), the drum axis AVV error waveform (H) from the drum axis AVV measured waveform (K) corresponding to the angular position of the load drum corresponding to the circumferential angular position θ = 0 to 2π of the tire. This is a waveform obtained by subtracting a value obtained by multiplying the tire / drum radius ratio (R ₁ ) of the reference tire by subtracting.

  Here, the variable δ1 of the AVV measurement waveform F (δ1) is set such that the rim phase at the mounting position determined as a reference at the relative mounting position of the rim 3 and the tire 2 is zero, It represents the phase. 10 (a) to 10 (b) are diagrams showing examples of the mounting positions. FIG. 10 (a) shows the reference mounting position corresponding to FIG. 9 (a), the tire 2 and the rim. FIG. 10B is a conceptual diagram showing a mounting position corresponding to FIG. 9B that is shifted by (2π / 8) radians.

In the present invention, the waveforms shown in FIGS. 9A to 9H are averaged to identify the tire AVV characteristic waveform (X ₁ ) of the reference tire 2A. Figure 9 (i) a tire AVV characteristic waveform of the reference tire 2A obtained by averaging thus (X ₁₎ indicates, the method of obtaining the above tire AVV characteristic waveform (X _1), the formula (3 ') Can be represented by

In this way, the principle of the method for identifying the tire AVV characteristic waveform (X ₁ ) is that the original waveform is shifted by a predetermined angle and the waveforms are averaged to cancel each other, and are added with the same phase. Only the component is based on the fact that only the tire AVV characteristic waveform (X ₁ ) remains in this case. Here, in order to cancel high-order harmonic components and extract only the tire AVV characteristic waveform (X ₁ ) with high accuracy, it is only necessary to increase M, but the processing time increases in inverse proportion to the accuracy. Therefore, M should be determined in consideration of these points.

  In this description, the tire is averaged for one round, but may be averaged for a plurality of rounds. In this case, it is possible to deal with a decrease in accuracy due to measurement variations.

  The AVV identification performed as described above is performed by the AVV control device 10, and the processing of the AVV control device 10 will be described with reference to the flowchart shown in FIG. To do. When the tire 2 is mounted on the rim 3 and inserted into the uniformity measuring device 1, the central control unit 24 of the AVV control device 10 determines the tire type and the reading sensor 11 provided in the device 1. The rim ID is read, and the read data is instructed to be output to the tire input unit 21 and the rim ID input 22 (step S1). Next, in step S2, the tire type data is received from the tire type input unit 21. Next, in step S3, the rim ID data is read from the rim ID input unit 22.

  Then, in step S4, the central control unit 24 (a) tire / drum radius ratio corresponding to the read tire type, (b) tire axis AVV error waveform corresponding to the read rim ID, and load drum to be used 5 (c), the drum axis AVV error waveform is downloaded from the parameter storage unit 23.

  On the other hand, after step S1, the central control unit 24 rotates the tire 2 at a predetermined rotational speed while pressing the tire 2 against the load drum 5 in parallel with the processing of steps S2 to S4. 9 then outputs a measurement start command to measure the tire angular velocity around the tire rotation axis 6 and acquire the tire axis AVV measurement waveform (step S5). ) The tire axis AVV measurement waveform is input (step S6). When the input of this data is completed, a measurement end command is output to the tire rotating device 4 (step S7).

  Next, the central control unit 24, in step S8, (a) tire / drum radius ratio, (b) tire axis AVV error waveform, (c) drum axis AVV error waveform, and (d) tire axis that have already been downloaded. Based on the AVV measurement waveform, the tire AVV characteristic waveform is obtained and identified by the method described above. Then, the identified tire AVV characteristic waveform and related information are displayed on the display device 14 (step S9) and transmitted to the factory management system 15 (step S10), and the series of processes is terminated.

  The present invention can be applied to uniformity measurement of various tires including passenger car tires and heavy duty vehicle tires.

It is a schematic perspective view which shows the basic composition of the uniformity measuring apparatus which concerns on this invention. It is a block diagram which shows the structure of an AVV control apparatus. It is process drawing which shows the process of calculating | requiring a tire AVV characteristic waveform. FIG. 4 is a positional relationship diagram representing the angular positions of a point P on a tire, a point Q on a rim, and a point R on a load drum 5 corresponding to each other by respective angular coordinates. It is a graph which illustrates the waveform used in connection with process M4 which identifies tire AVV characteristic waveform (X). It is a graph which illustrates the waveform used in connection with process P1a which identifies a drum axis AVV error waveform (H). It is a positional relationship figure which shows the contact position relationship between a load drum and a tire. It is a graph which illustrates the waveform used in connection with process P2a which identifies a tire axis AVV error waveform (G). It is a graph which illustrates the waveform used when identifying the tire AVV characteristic waveform of a reference tire. It is a positional relationship figure which shows the relative mounting position of a rim | limb and a tire. 4 is a flowchart showing processing of an AVV control device in a measurement process M.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Uniformity measuring device 2 Tire 3 Rim 4 Tire rotating device 5 Load drum 6 Tire rotating shaft 7 Load drum rotating shaft 8 Encoder 9 Tire axial angular velocity variation measuring device 10 AVV control device 11 Reading sensor 12 Tire type reading sensor 13 Rim ID reading Sensor 14 Display device 15 Factory central control device 16 Encoder 17 Drum shaft angular velocity fluctuation measuring instrument 21 Tire type input unit 22 Rim ID input unit 23 Parameter storage unit 24 Central control unit

Claims (6)

The tire mounted on the rim is rotated at a predetermined rotational speed while being pressed against the peripheral surface of a load drum that is rotatably provided around an axis parallel to the rotation axis. Angular velocity variation), and the tire shaft AVV measurement waveform obtained by measuring the angular velocity variation) and the drum shaft AVV measurement waveform obtained by measuring the angular velocity variation of the load drum around the drum rotation axis. In a uniformity measuring method for identifying a tire AVV characteristic waveform representing a characteristic,
F is the tire axis measurement waveform in the tire phase range Σ for one tire lap, and K is the drum axis measurement waveform in the drum phase range Ψ corresponding to the tire phase range Σ as a contact range between the peripheral surfaces. These tires F, K, tire shaft AVV error waveform G and drum shaft AVV error waveform H, which are identified in advance and appear independently of the tire, are substituted into equation (1), and the tire AVV characteristics are obtained. Tire uniformity measurement method that identifies waveform X.

However,
X: Tire AVV characteristic waveform in the tire phase range Σ
F: Tire axis measurement waveform in the tire phase range Σ
K: Drum axis measurement waveform in drum phase range Ψ
H: Drum axis AVV error waveform
R: Tire / drum radius ratio (ratio of tire rolling radius to load drum radius)
G: Tire axis AVV error waveform When the tire axis AVV error waveform G in the equation (1) is identified, the tire axis measurement waveform obtained by mounting a reference tire having a known tire AVV characteristic waveform on the rim and rotating the tire one or more times. The tire uniformity measurement method according to claim 1, wherein the tire axis AVV error waveform G is obtained from F ₁ and the drum axis measurement waveform K ₁ by using the tire AVV characteristic waveform of the reference tire as X ₁ and using Equation (2). .

However,
X ₁ : Tire AVV characteristic waveform of the reference tire
F ₁ : Tire axis AVV measurement waveform when the reference tire is installed
K ₁ : Drum axis AVV measurement waveform when the reference tire is installed
H: Drum axis AVV error waveform
R ₁ : Tire / drum radius ratio relative to the reference tire
G: Tire axis AVV error waveform   A tire is mounted on a rim at a plurality of mounting positions that are different from each other in phase with the rim, and a tire axis AVV error waveform is calculated for each mounting position based on the uniformity measurement method according to claim 2. A method for measuring tire uniformity, wherein the tire axis AVV error waveform obtained corresponding to each mounting position is averaged and identified as the tire axis AVV error waveform of the rim.   In identifying the drum axis AVV error waveform H in the formula (1) and / or (2), the tire is rotated by (2π / N) radians with N being an integer of 2 or more, or randomly selected. The tires are pressed against the load drum at a predetermined rotational speed for each of the N contact positions of the load drum and the tire obtained by rotating N times each angle and contacting the load drum. 2. The drum drum measurement waveform obtained by rotating at least one rotation of the load drum and averaging the N drum shaft measurement waveforms obtained at this time is used as the drum shaft AVV error waveform H. The measurement method of the tire uniformity in any one of -3. When identifying the tire AVV characteristic waveform X ₁ of the reference tire in the above formula (2), M is an integer equal to or larger than 2, and M pieces are mounted on the rim, the phases of which are different from each other by (2π / M) radians. The tires obtained by mounting the reference tire at M mounting positions that are different from each other by a position or a randomly selected angle, and rotating the tire one or more times with respect to each mounting position i. The tire uniformity measurement according to any one of claims 2 to 4, wherein a tire AVV characteristic waveform of a reference tire is obtained from an axis measurement waveform F (i) and a drum axis measurement waveform K (i) using Equation (3). Method.

However,
X ₁ : Tire AVV characteristic waveform
F (i): Tire axis measurement waveform corresponding to the i-th tire mounting position
K (i): Drum axis measurement waveform corresponding to the i-th tire mounting position
H: Drum axis AVV error waveform
R ₁ : Tire / drum radius ratio relative to the reference tire
A tire uniformity measuring device used in the tire uniformity measuring method according to claim 1,
Tire rotating device for rotating a rim on which a tire is mounted, the load drum, each encoder for detecting the rotation angle position of the tire and the load drum, and the angular velocity of the tire and the load drum based on signals from these encoders Each angular velocity fluctuation measuring device for obtaining fluctuations, and an AVV control device for calculating the tire AVV characteristic waveform based on signals from these angular velocity fluctuation measuring devices,
The AVV control device includes a tire type input unit for inputting a tire type to be measured from the outside, a rim ID input unit for inputting an identification code of a rim used for measurement from the outside, and parameters used for calculating a tire AVV characteristic waveform. A parameter storage unit for storing, and a central control unit for calculating the tire AVV characteristic waveform,
The parameter storage unit stores at least the drum axis AVV error waveform, a tire / drum radius ratio for each tire type, and a tire axis AVV error waveform for each rim ID,
The central control unit includes the drum axis AVV error waveform, the tire / drum radius ratio corresponding to the tire type input to the tire type input unit, and the tire axis AVV corresponding to the rim ID input to the rim ID input unit. The error waveform is read from the parameter storage unit, and the tire axis AVV measurement waveform is created based on the signal from the tire shaft angular velocity fluctuation measuring device, and also based on the signal from the drum shaft angular velocity fluctuation measuring device. The drum axis AVV measurement waveform is created, and based on these measurement waveform, the tire / drum radius ratio, the tire axis AVV error waveform, and the drum axis AVV error waveform read from the parameter storage unit, the tire AVV characteristics are obtained. A tire uniformity measuring apparatus configured to perform processing for identifying a waveform.

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