JP2006105773A - Tire uniformity measuring apparatus and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire uniformity measuring apparatus capable of highly accurately measuring AVV (angular velocity variations) by easily altering an existing apparatus, and provide its manufacturing method. <P>SOLUTION: The tire uniformity measuring apparatus 1 has an AVV sensor for detecting angular velocity. The AVV sensor comprises both an encoder 16 and an angular velocity variation measuring device for computing an angular velocity variation waveform of a rotating support 32. The encoder 16 is constituted of a dial 37 and a plurality of graduation readers 38A and 38B. The dial 37 is arranged in the periphery of a shaft 42. Graduations are arranged at regular intervals. The graduation readers are arranged in a circumference in such a way that their phases may be different from each other. The angular velocity variation measuring device is constituted of AVV converters 17A and 17B and an AVV waveform generation part for compensating for data missing parts corresponding to discontinuous parts in angular velocity variation waveforms of the AVV converters 17A and 17B and generating an angular velocity variation waveform indicating changes in angular velocity of the rotating support. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a tire uniformity measuring apparatus for identifying AVV (angular velocity variation) used as a substitute characteristic of TFV (tangential force variation) of a tire and a manufacturing method thereof, and more particularly, to an existing tire uniformity measuring apparatus. It is related with the thing suitable for the thing which remodeled and enabled it to measure AVV with high precision.

  Recently, as part of product inspection, in addition to tire RFV (radial force variation) and LFV (lateral force variation), TFV (tangential force variation) has been inspected. Alternatively, instead of directly measuring TFV, it is now possible to inspect the AVV (and angular velocity variation, angular velocity fluctuation) of a tire that can be measured more easily and can substitute the characteristics of TFV. I came.

  In order to measure the AVV of a tire, the tire is mounted on a rim, and the tire is pressed against the peripheral surface of a load drum provided to be rotatable around a straight line parallel to the tire rotation center line under a predetermined torque condition. , The angular velocity of the tire and the angular velocity of the load drum are measured, and the AVV of the tire is identified based on the obtained AVV (angular velocity fluctuation) waveform. (For example, refer to Patent Document 1.)

  The measured AVV waveform is directly used as the tire AVV waveform and the amplitude is set to the tire AVV. However, the AVV waveform obtained by the measurement is more or less the tire-specific AVV characteristic. In addition to the tire axis AVV measurement error and drum axis AVV measurement error that appear regardless of the tire due to the error of the measuring instrument, etc., the waveform is superimposed with the influence of the angular velocity fluctuation of the load drum accelerated / decelerated by the tire AVV. In order to specify the tire AVV with high accuracy, it is necessary to subtract these influences from the measured waveform. For this purpose, the AVV waveform around the load drum axis must be measured.

  However, in general, the conventional uniformity measuring device is not configured to measure the angular velocity of the load drum, and the existing uniformity measuring device is modified to directly detect the rotation position of the load drum. In order to convert the pulse train from the encoder into an angular velocity, an endless circular scale plate is attached to the part rotating with the load drum on the outer side in the radial direction of the shaft located at the drum rotation center. It must be configured to generate pulses by reading the graduation on the board moving in the circumferential direction. For this purpose, if the existing shaft is supported at both ends, remove this shaft from the bearing. It is necessary, and the construction cost and the period become enormous.

  Further, as an alternative method, for example, a method of attaching a split gear to the shaft and providing a scale plate to be engaged with the shaft at a position away from the shaft can be considered, but a split gear is used. There is a problem that the accuracy decreases by the amount.

  The present invention has been made in view of such problems, and a tire uniformity measuring apparatus and method for manufacturing the same that can easily modify an existing apparatus to measure AVV with high accuracy. The purpose is to provide.

<1> is a rim on which a tire is mounted, a load drum arranged so as to press the tire and the circumferential surface against each other, a tire rotating support that rotates with the rim fixed on the circumference, and the load drum fixed on the circumference A rotating drum support that rotates and an AVV sensor that detects an angular velocity fluctuation (AVV) of at least one of these rotating supports, and identifies a tire-specific AVV characteristic waveform based on a signal from the AVV sensor In the tire uniformity measuring device
The AVV sensor includes an encoder that detects a rotation angle position of a corresponding rotation support, and an angular velocity variation measuring instrument that calculates an angular velocity variation waveform of the rotation support based on a pulse train signal from the encoder,
At least one of the encoders has a plurality of scales engraved on the board, and is opposed to the scale board fixed to the rotary support and rotating, and the non-rotating side and the board surface on which the scales are engraved. It is composed of a plurality of scale readers that read the scale moving with the rotation of the scale board and generate pulses,
The scale plate is arranged around the shaft that pivotally supports the rotation support body or constitutes the rotation center portion of the rotation support body, and has an annular shape having one or more discontinuous parts in the circumferential direction part, The graduations are arranged at equal intervals on the circumference excluding the discontinuous portion, and the graduation readers are arranged in different phases on the circumference around the rotation center of the rotation support. Arranged,
An angular velocity fluctuation measuring device corresponding to the encoder having a plurality of scale readers, each AVV converter for directly converting a pulse train signal from the scale reader into an angular velocity fluctuation waveform, and the angular velocity fluctuation waveforms of the angular velocity fluctuation waveforms, It is a tire uniformity measuring device configured with an AVV waveform generation unit that generates an angular velocity fluctuation waveform representing an angular velocity change of the rotating support by complementing a data missing portion corresponding to the discontinuous portion.

  <2> is that in <1>, the AVV waveform generation unit divides a phase range of 2π radians corresponding to one rotation of the rotating support with a phase in which the number of scale readers corresponding to the data missing part changes. Are divided into a plurality of sections, and for each section, only the data of the scale reader that does not correspond to the data missing portion is processed by averaging with a predetermined weight to generate the angular velocity fluctuation waveform of the rotating support. A tire uniformity measuring apparatus configured to perform the above.

  <3> is that in <1> or <2>, one AVV sensor is provided corresponding to each of the tire rotation support and the drum rotation support, and at least on the side corresponding to the drum rotation support The AVV sensor is a tire uniformity measuring device including the encoder having a plurality of scale readers and the angular velocity variation measuring device corresponding to the encoder.

  <4> is a method for manufacturing the tire uniformity measuring apparatus according to any one of <1> to <3>, and when the encoder is formed, the endless ring is formed after the scale is formed on the endless ring. A part of the annular ring in the circumferential direction is notched, and the shaft is arranged in the center of the annular ring through the notch from the radially outer side of the notched annular ring, or the endless annular ring is divided in the circumferential direction so that It is a manufacturing method of the tire uniformity measuring apparatus which arrange | positions the divided | segmented part around the said shaft and becomes the said scale board.

According to the invention of <1>, at least one of the encoders has a plurality of scales carved on the board, and is fixed to the rotary board fixed to the rotary support and fixed to the non-rotating side, Since it is composed of a plurality of scale readers that read the scale moving with the rotation of the scale board and generate a pulse, facing the board surface on which the scale is engraved, the rotation of the rotating support is Because it reads directly without going through gears etc., it can generate pulses with high precision timing,
Further, the scale plate is formed in an annular shape having one or more discontinuous portions in a part in the circumferential direction, which is arranged around the shaft. From the outside in the radial direction, the shaft can be arranged at the center of the ring through the notch, or the endless ring can be divided in the circumferential direction and the divided parts can be arranged around the shaft. When fixing the scale plate to the rotating support, even if the shaft is supported at both ends, the shaft can be directly attached to the rotating support without removing it from the support, and the existing tire uniformity measuring device can be installed. Even when remodeling and installing the encoder, this installation can be done easily,
Further, the angular velocity fluctuation measuring device includes respective AVV converters that directly convert the pulse train signals from the scale readers into angular velocity fluctuation waveforms, and data missing portions corresponding to the discontinuous portions of these angular velocity fluctuation waveforms. Complementarily, since it is composed of an AVV waveform generation unit that generates an angular velocity fluctuation waveform representing the angular velocity fluctuation of the rotary support, even if the scale plate has a discontinuous portion, accuracy is not sacrificed. By generating an angular velocity fluctuation waveform of the rotating support, the AVV of the tire can be identified.

  According to the invention of <2>, the AVV waveform generation unit divides a phase range of 2π radians corresponding to one rotation of the rotary support with a phase in which the number of scale readers corresponding to the data missing part changes. Dividing into a plurality of sections, and for each section, performing the process of weighted averaging only the data of the scale reader that does not correspond to the data omission part, the angular velocity fluctuation waveform of the rotating support is generated, so one The data missing portion of the scale reader can be supplemented with the data of other scale readers, and the data can be smoothly continued across the boundaries by this averaging process.

  According to the invention <3>, one AVV sensor is provided corresponding to each of the tire rotation support and the drum rotation support, and at least the AVV sensor on the side corresponding to the drum rotation support is a scale. Since the encoder includes a plurality of readers and the angular velocity fluctuation measuring device corresponding to the encoder, the tire rotation support for supporting the tire is used to obtain a tire-specific AVV waveform as will be described later. In addition to measuring the angular velocity of the body, it is possible to identify the AVV characteristics of the load drum by measuring the angular velocity fluctuation waveform of the drum rotation support, and from the measured AVV waveform of the tire rotation support, the AVV waveform of the load drum The AVV waveform of only the tire can be obtained by subtracting.

  According to the invention <4>, when the encoder is formed, the scale is formed on the endless ring, and then a part in the circumferential direction of the endless ring is cut away from the radially outer side of the notched ring. The shaft is arranged at the center of the ring through the notch, or the endless ring is divided in the circumferential direction and the divided parts are arranged around the shaft to form the dial plate. As explained above, the scale plate can be fixed to the rotating support without removing the shaft from the support part even if both shafts are held, and the scale is attached in an endless ring state. Thus, the scale can be assigned 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 tire AVV (angular velocity fluctuation), and FIG. 2 is a block diagram showing a flow of information in the uniformity measuring apparatus. . The uniformity measuring apparatus 1 includes a rim 3 on which a tire 2 is mounted, a load drum 5 arranged so as to press the tire 2 against its peripheral surface, a tire rotating support 31 that rotates with the rim 3 fixed on the circumference, a load A drum rotation support 32 that rotates with the drum 5 fixed on the circumference, and an AVV sensor that detects angular velocity fluctuations of the rotation supports 31 and 32 are provided.

  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 information on the tire type and the rim ID is necessary for identifying the AVV of the tire, but is not limited to these sensors 12 and 13 but can be added by other means such as a computer. It is also possible to acquire such information by tracing the tire that has been vulcanized and the rim to be used from the initial stage.

  The AVV sensor on the side that detects the angular velocity fluctuation of the tire rotation support 31 includes a tire shaft encoder 8 that detects the rotation angle position of the tire rotation support 31, and the tire rotation support 31 based on the pulse train signal from the encoder 8. An angular velocity fluctuation measuring device for calculating an angular velocity fluctuation waveform is constituted by a tire axis AVV converter 9 for converting a pulse train signal into an angular velocity fluctuation waveform.

  On the other hand, the AVV sensor on the side that detects the angular velocity of the drum rotation support 32 has a drum shaft encoder 16 that detects the rotation angle position of the drum rotation support 32, and the drum rotation support 32 based on the pulse train signal from the encoder 16. The drum-side angular velocity fluctuation measuring device 19 converts a plurality of (two in the illustrated example) pulse train signals output from the encoder 16 into angular velocity fluctuation waveforms. Based on the respective drum axis AVV converters 17A and 17B and the angular speed fluctuation waveforms output from these drum axis AVV converters 17A and 17B, a unique angular speed fluctuation waveform representing the angular speed fluctuation of the drum rotating support 32 is generated. And an AVV waveform generation unit 18 that performs the same.

  The angular velocity fluctuation waveform from the tire shaft AVV converter 9 obtained by rotating the tire 2 while pressing the tire 2 against the load drum 5 is input to the AVV control device 10, and the AVV control device 10 calculates the tire based on the angular velocity fluctuation waveform. 2 are identified, and the angular velocity fluctuation waveform from the tire shaft AVV converter 9 at this time is the tire AVV characteristic waveform due to the error of the measuring instrument and the like. In addition to the tire axis AVV measurement error and drum axis AVV measurement error that appear irrelevantly, the influence of the angular velocity fluctuation of the load drum accelerated / decelerated by the tire AVV is superimposed, and the AVV of the tire is specified with high accuracy. In order to do this, it is necessary to subtract these effects from the measured waveform. For this purpose, the AVV waveform around the load drum axis must be measured, and the AVV control apparatus 10 performs such processing.

  In order to cancel out the influence of the angular velocity fluctuation of the loaded drum accurately, the AVV control device 10 of the uniformity measuring apparatus 1 performs the drum axis AVV based on the angular velocity fluctuation waveforms input from the drum axis AVV converters 17A and 17B. The measurement waveform can be generated.

  The AVV control device 10 having the functions as described above is configured so that the tire type input unit 21 that inputs the tire type of the tire to be measured from the external reading sensor 11 and the identification code of the rim used for the measurement are similarly read from the reading sensor 11. A rim ID input unit 21 for inputting, a parameter storage unit 23 for storing parameters used for calculating the tire AVV, and a central control unit 24 for calculating the tire AVV are provided.

  The parameter storage unit 23 stores at least a tire / drum radius ratio for each tire type, a rim component waveform for each rim ID, and an identified drum angular velocity fluctuation waveform identified by measurement in advance, while central control is performed. The unit 24 corresponds to the drum angular velocity fluctuation waveform from the parameter storage unit 23, the tire / drum radius ratio corresponding to the tire type input to the tire type input unit 21, and the rim ID input to the rim ID input unit 22. The tire rim component waveform is read out, a tire axis AVV measurement waveform is created based on the signal from the tire axis AVV converter 9, and the tire axis AVV measurement waveform and the tire / drum radius ratio read out from the parameter storage unit 23 are read. The tire AVV characteristic waveform is identified based on the rim component waveform and the drum angular velocity fluctuation waveform. The tire / drum radius ratio represents the ratio of the tire radius to the drum radius in a state where the peripheral surfaces are pressed against each other and rotated.

  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.

  Next, each AVV sensor which detects the angular velocity of the tire rotation support body 31 and the drum rotation support body 32 is demonstrated in detail below. As described above, the AVV sensor that detects the angular velocity fluctuation of the tire rotation support 31 includes the tire axis encoder 8 and the tire axis AVV converter 9 that converts the pulse train signal from the encoder 8 into the angular velocity fluctuation.

  The AVV converter 9 only needs to convert the pulse interval information of the pulse train from the encoder 8 into a signal representing angular velocity fluctuation. For example, an FM demodulator that demodulates a frequency-modulated FM pulse train signal, a frequency deviation, etc. A measuring instrument such as KAZ-723 (model number) manufactured by Cocoresearch may be used.

  3A is a partial cross-sectional view showing the tire axis encoder 8, FIG. 3B is an arrow view corresponding to the arrow b1-b1 in FIG. 3A, and the tire axis encoder 8 is A scale plate 35 that is fixed to the tire rotation support 31 that supports the rim 3 and has a plurality of scales 35a carved on the board and rotates, and a board surface that is fixed on the non-rotating side and on which the scales 35a are carved. And a single scale reader 36 that reads a scale 35a that moves in accordance with the rotation of the scale board 35 and generates a pulse. The scale plate 35 is formed in an endless annular shape arranged around a shaft 41 that supports the tire rotation support 31, and the scale 35 a is arranged in the circumferential direction at equal intervals.

  In FIG. 3A, 4 is a tire rotating device that rotates the tire, and 44 is a support portion that cantilever-supports the shaft 41, and a non-rotating side portion that fixes the scale reader 36. Constitute.

  Here, the scale 35a may be engraved on the scale board, or may be formed by a slit penetrating the front and back of the scale board. When this is formed by the slit, the scale reading of the scale board 35 is performed. A light source for passing light through the slit is provided on the side opposite to the container 36 side.

  On the other hand, as described above, the AVV sensor that detects the angular velocity of the drum rotation support 31 includes the drum shaft encoder 16 and a plurality of drum shaft AVV converters 17A that convert pulse train signals from the encoder 16 into angular velocity fluctuations. 17B and an AVV waveform generation unit 18 that generates a drum angular velocity fluctuation waveform representing an angular velocity fluctuation of the drum rotating support 31 based on the angular velocity fluctuation waveforms from the AVV converters 17A and 17B.

  The drum shaft AVV converters 17A and 17B may be the same as the tire shaft AVV converter 9 and may be any one that converts the pulse interval information of the pulse train from the encoder 8 into a signal representing the angular velocity fluctuation. For example, an FM demodulator that demodulates a frequency-modulated FM pulse train signal or a frequency deviation measuring instrument, such as KAZ-723 (model number) manufactured by Cocoresearch, can be used.

  4A is a partial cross-sectional view showing the drum axis encoder 16, FIG. 4B is an arrow view corresponding to the arrow b2-b2 in FIG. 4A, and the drum axis encoder 16 is A scale plate 37 having a plurality of scales 37a carved on the board, fixed to the drum rotation support body 32 and rotated, and fixed to the non-rotating side, and arranged facing the board surface on which the scales 37a are carved. The graduation unit 37A includes a plurality of graduation readers 38A and 38B that read the graduation 37a that moves as the graduation plate 37 rotates and generate pulses. The scale plate 37 is disposed around a shaft 42 that supports the tire rotation support 31 and has an annular shape having one discontinuous portion 37D in a part of the circumferential direction.

  The scales 37a are arranged at equal intervals on the circumference excluding the discontinuous portion 37D. Here, the discontinuous portion 37 </ b> D functions as an opening for inserting the shaft 42 into the center portion of the scale plate 37 from the outside in the radial direction of the scale plate 37.

  As described above, the scale plate 37 has an opening for inserting the shaft 42, so that the encoder 16 is attached to the uniformity measuring apparatus 1 without the encoder 16 to measure the angular velocity fluctuation of the load drum. In this case, if the scale plate 37 having no opening is used, the shaft 42 must be temporarily detached from the support portions 45A and 45B and attached to the rotary support 32 through the scale plate 32 to the shaft 42. In, the scale plate 37 can be fixed to the drum rotation support 32 without removing the shaft 42 from the support portions 45A and 45B.

  Here, the scale 37a may be engraved on the scale board, and may be formed by a slit penetrating the front and back of the scale board, similarly to the scale 35a.

  The scale readers 38A and 38B are arranged on the circumference around the rotation center of the drum rotation support 32 so as to have different phases from each other, respectively, and read the scales 37a passing through different parts in the circumferential direction, respectively. appear. In the figure, reference numerals 45A and 45B denote support portions that support the shaft 42 at both ends, and the support portion 45A constitutes a non-rotating side portion that fixes the scale readers 38A and 38B.

  The scale plate 37 can be formed by forming the scales 37a on the endless ring so as to be arranged at equal intervals, and then cutting away a part of the endless ring to form a discontinuous portion 37D. By doing so, the scale 37a can be arranged at equal intervals with high accuracy.

  Instead of the scale plate 37, the scale plate 57 shown in the arrow view corresponding to b2-b2 of FIG. 4A can also be used in FIG. The scale plate 57 is composed of divided portions 57a, 57b, and 57c divided into three from an endless ring, and these divided portions 57a, 57b, and 57c are interposed via minute gaps 59a, 59b, and 59c that become discontinuous portions. They are arranged adjacent to each other in the circumferential direction, and form an annular shape having discontinuous portions 59a, 59b, 59c as a whole. In this case, it is preferable to use three scale readers 57A, 57B, and 57C instead of the two scale readers 38A and 38B.

  The scale plate 57 is formed by forming the scale 57a on the endless ring so as to be equally spaced, and then dividing the endless ring into three in the circumferential direction, and arranging the divided portions 57a, 57b, 57c around the shaft 42. It is only necessary to fix to the drum rotation support body 32. By forming the scale plate 57 by this method, it is not necessary to remove the shaft 42 from the support portions 45A and 45B, and the endless ring is scaled. A highly accurate scale interval can be secured.

  The angular velocity fluctuation waveforms output from the AVV converters 17A and 17B have a data missing part corresponding to the discontinuous part 37D, and the AVV waveform generating part 18 complements the data missing part to provide a drum rotation support part. An angular velocity fluctuation waveform representing 32 angular velocity changes is generated. FIG. 5 is a graph showing the generation method, in which the vertical axis indicates the angular velocity, the horizontal axis indicates the drum circumferential position expressed in radians with a predetermined position as the origin.

  In the figure, line A is the angular velocity fluctuation waveform from the AVV converter 17A, line B is the angular velocity fluctuation waveform from the AVV converter 17B, and line C is the angular velocity fluctuation of the rotary support 32 based on the lines A and B. The angular velocity fluctuation waveform generated as a representation of the data is shown, where the section α1 at the circumferential position is the phase range corresponding to the data missing portion of the line A, and the section α3 is the phase range and section corresponding to the data missing portion of the line B. α2 and α4 are phase ranges in which neither the line A nor the line B includes the data missing part, and the number of scale readers corresponding to the data missing part is the phase that becomes the break of these sections. 1 to 2 or 2 to 1.

  And line C performs weighted averaging processing of only the data of the scale reader that does not correspond to the data missing portion of line A and line B for each of the sections α1 to α4 thus partitioned. In the case of the figure, in the sections α2 and α4, the data of the lines A and B are averaged with a predetermined weight, and in the section α1, only the data of the line B is averaged, that is, Similarly, the data of the line B is complemented by using the data as it is. Similarly, in the section α3, only the data of the line A is averaged, that is, the data of the line A is complemented by using the data as it is. In addition to complementing the data, the data can be smoothly continued between the sections.

  As an example of weighting, for example, in the vicinity of the section α1 corresponding to the data missing part of line A, the weight of line B is larger than the weight of line A (for example, the weights of line B and line A are 0.9 and 0.1, respectively). The weight ratio approaches 1 as the distance from the section α1 increases. In the phase range sufficiently away from the section α1, the weight ratio is 1, while the vicinity of the section α3 corresponding to the data missing portion of the line B Then, the weight of the line A is larger than the weight of the line B, and as the distance from the section α3 is increased, the weight ratio is made closer to 1. In the phase range sufficiently away from the section α3, the weight ratio is set to 1. it can.

  As is apparent from the processing content of the AVV waveform generation unit 18 described above, when the scale readers 38A and 38B are arranged, it is preferable that they are not located in the discontinuous part 37D at the same time.

  In the above description, the scale plate of the encoder 8 corresponding to the tire rotation support body 31 is an endless annular one. However, in consideration of the case where it will be replaced in the future, the same configuration as the drum shaft encoder 16 is used. It can also be. The angular velocity fluctuation measuring instrument in that case has the same configuration as the angular velocity fluctuation measuring instrument 19 corresponding to the drum axis.

  A method for obtaining a tire AVV characteristic waveform using such an apparatus 1 will be described. FIG. 6 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 with reference to FIGS. FIG. 7 is shown to assist in understanding the following description. In the state where the tire 2 mounted on the rim 3 and the load drum 5 are in contact with each other, the points P on the tire corresponding to each other are shown. 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. 8A 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. 8B 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. 8C 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. 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. 8D 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. For this reason, 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 shown in FIGS. 8A to 8D based on the equation (1). FIG. The tire AVV characteristic waveform (X) thus determined for the circumference 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. . 9 (a) to 9 (h) show that the tire 2 is mounted on the rim 3 and the tire 2 is fixed to (2π / N) radians (N in the illustrated case) 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. 10A to FIG. 10C are diagrams showing examples of this contact position relationship, and FIG. 10A shows a reference contact position relationship corresponding to FIG. FIG. 10B is a conceptual diagram showing the relative position between the tire 2 and the load drum 5. FIG. 10B shows the contact position relationship corresponding to FIG. 9B, which is shifted by (2π / 8) radians. FIG. 10C is a conceptual diagram showing the contact position relationship corresponding to FIG. 9D, 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. 9 (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. 11A is obtained by using the uniformity measuring apparatus 1 shown in FIG. 1 and having the tire AVV characteristic waveform known and rotating the reference tire 2A at a predetermined rotational speed while being pressed 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. 11B shows the drum axis AVV measurement waveform (K ₁ ) in the drum axis phase range Ψ (ψ = ψ _{0 to} ψ ₀ + 2π) corresponding to the tire axis phase range Θ, with respect to the reference tire 2A. 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. 11C shows a known tire AVV characteristic waveform (X ₁ ) of the reference tire 2A, in which the tire axis phase range Θ (θ = 0 to 6π), that is, three tire laps is continuously shown. It is. A method for identifying this will be described later separately.

FIG. 11D shows the load drum 5 in the drum shaft phase range ψ (ψ = ψ _{0 to} ψ ₀ + 2π) (see FIG. 7) 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 equation (2).

FIG. 11 (e) 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. 11 (f) 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 while changing the phase, and the tire axis AVV error waveform (G (j ₁ )) is obtained based on the equation (2) for each of the mounting positions having different phases. The tire axis AVV error waveform (G (j ₁ )) can also be averaged by obtaining the values obtained for the mounting position of the tire, and in this case, the dependency on the mounting position is eliminated and the tire axis AVV error waveform is eliminated. (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. 12 (a) to 12 (h) show the mounting position 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 phase of the rim 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. FIGS. 13A to 13B are views showing examples of the mounting positions. FIG. 13A shows the reference mounting positions corresponding to FIG. FIG. 13B is a conceptual diagram showing the mounting position corresponding to FIG. 12B that is shifted by (2π / 8) radians.

In the present invention, the waveforms shown in FIGS. 12A to 12H are averaged to identify the tire AVV characteristic waveform (X ₁ ) of the reference tire 2A. Figure 12 (i) shows the tire AVV characteristic waveform of the reference tire 2A obtained by averaging thus (X _1), the method for obtaining the above tire AVV characteristic waveform (X _1), the equation (3) Can be represented.

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 apparatus 10, and the process of the AVV control apparatus 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 flow of the information in a uniformity measuring apparatus. It is sectional drawing and an arrow view which show a tire shaft encoder. It is sectional drawing and arrow view which show a drum axis encoder. It is a graph which shows the method of complementing the data missing part of the original angular velocity fluctuation waveform, and producing | generating the angular velocity fluctuation waveform showing the angular velocity change of a drum rotation support part. It is process drawing which shows the process of calculating | requiring the AVV characteristic waveform of a tire. 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 apparatus 2 Tire 3 Rim 4 Tire rotating apparatus 5 Load drum 8 Tire axis encoder 9 Tire axis AVV converter 10 AVV control apparatus 11 Reading sensor 12 Tire type reading sensor 13 Rim ID reading sensor 14 Display apparatus 15 Factory central management Device 16 Drum axis encoder 17A, 17B Drum axis AVV converter 18 AVV waveform generation unit 21 Tire type input unit 22 Rim ID input unit 23 Parameter storage unit 24 Central control unit 31 Tire rotation support unit 32 Drum rotation support unit 35 Scale plate 35a Scale 36 Scale reader 37 Scale 37a Scale 37D Discontinuous part 38A, 38B Scale reader 41, 42 Shaft 44, 45A, 45B Support part 57 Scale 57a, 57b, 57c Split part 58A divided from endless ring 58B, 58C Scale reader 59a, 59b, 59c Minute gap that becomes discontinuous part

Claims (4)

A rim on which a tire is mounted, a load drum arranged so as to press the tire and the circumferential surface against each other, a tire rotating support that rotates with the rim fixed on the circumference, and a drum that rotates with the load drum fixed on the circumference Tire uniformity measurement that includes a rotating support and an AVV sensor that detects angular velocity fluctuations (AVV) of at least one of these rotating supports, and that identifies a tire-specific AVV characteristic waveform based on a signal from the AVV sensor In the device
The AVV sensor includes an encoder that detects a rotation angle position of a corresponding rotation support, and an angular velocity variation measuring instrument that calculates an angular velocity variation waveform of the rotation support based on a pulse train signal from the encoder,
At least one of the encoders has a plurality of scales engraved on the board, and is opposed to the scale board fixed to the rotary support and rotating, and the non-rotating side and the board surface on which the scales are engraved. It is composed of a plurality of scale readers that read the scale moving with the rotation of the scale board and generate pulses,
The scale plate is arranged around the shaft that pivotally supports the rotation support body or constitutes the rotation center portion of the rotation support body, and has an annular shape having one or more discontinuous parts in the circumferential direction part, The graduations are arranged at equal intervals on the circumference excluding the discontinuous portion, and the graduation readers are arranged in different phases on the circumference around the rotation center of the rotation support. Arranged,
An angular velocity fluctuation measuring device corresponding to the encoder having a plurality of scale readers, each AVV converter for directly converting a pulse train signal from the scale reader into an angular velocity fluctuation waveform, and the angular velocity fluctuation waveforms of the angular velocity fluctuation waveforms, A tire uniformity measuring device comprising an AVV waveform generation unit that generates an angular velocity fluctuation waveform representing an angular velocity fluctuation of the rotating support by complementing a data missing portion corresponding to the discontinuous portion.   The AVV waveform generation unit divides a phase range of 2π radians corresponding to one rotation of the rotary support into a plurality of sections by dividing the phase range by the number of scale readers corresponding to the data omission part. 2. The angular velocity fluctuation waveform of the rotating support is generated for each section by performing a process of averaging only the data of the scale reader that does not correspond to the data missing portion with a predetermined weight, and generating the angular velocity fluctuation waveform of the rotating support. The tire uniformity measuring device described.   One AVV sensor is provided corresponding to each of the tire rotation support and the drum rotation support, and at least the AVV sensor on the side corresponding to the drum rotation support includes the encoder having a plurality of scale readers. The tire uniformity measuring device according to claim 1 or 2, comprising the angular velocity variation measuring instrument corresponding to the encoder.   It is a method of manufacturing the tire uniformity measuring device according to any one of claims 1 to 3, and when forming the encoder, after forming the scale on the endless ring, the circumferential direction of the endless ring A part is notched, and the shaft is arranged in the center of the ring through the notch from the outside in the radial direction of the notched ring, or the endless ring is divided in the circumferential direction and the divided parts are A method for manufacturing a tire uniformity measuring device arranged around the shaft and serving as the scale plate.

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