JPH06182903A - Manufacture of radial tire - Google Patents

Abstract

PURPOSE:To reduce sufficiently force variation in a radial direction of each tire. CONSTITUTION:In an RRO waveform measuring process an RRO waveform of each green tire 10 is extracted. In a vulcanization factor waveform recording process a vulcanization factor waveform of a vulcanization mold 20 is recorded in a storage element 16A of a computer 16 every vulcanizer among a plurality of vulcanizers. In a selection process, the RRO waveform of the green tire 10 is superimposed on the vulcanization factor waveform of the vulcanization mold 20 to make a composite wave, and the composite wave which minimizes an RRO waveform amplitude of a vulcanized tire is selected. In a marking process, a superimposed angle theta of the green tire 10 wherein the RRO waveform amplitude of the vulcanized tire is minimized is determined to a peripheral standard position of the vulcanized mold 20 based on the selected composite wave. A mark 28 is marked at a specific position on a periphery of the green tire 10 with a marking device 26. In a vulcanization process, the mark 28 marked in the marking process is fitted to a stencil position 20A of the vulcanized mold 20, and the green 10 is arranged in the vulcanization mold 20 to be vulcanized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a radial tire, and more particularly to a method for manufacturing a radial tire with reduced RFV of the radial tire.

[0002]

2. Description of the Related Art Conventionally, in a radial tire, unevenness in a radial direction of a green tire (hereinafter referred to as RRO) due to molding of a tire constituent member and a vulcanization factor of a vulcanizer cause a radial direction in a vulcanized tire. Force variation (RFV) occurs. The RFV of this tire is
It will seriously affect the riding comfort and steering stability of the vehicle.

Therefore, the positive or negative maximum amplitude position of the green tire force variation average waveform as a forming factor and the negative or positive maximum amplitude position of the vulcanization mold force variation average waveform as a vulcanizing factor are defined. A method of manufacturing a radial tire in which a green tire is placed in a vulcanization mold so that the distance is within 20 ° and the force variation average waveforms of the green tire and the green tire are offset from each other is disclosed.
-145135.

However, in this radial tire manufacturing method, eight green tires are arranged in a predetermined vulcanizing mold by rotating them by 45 °, and each force variation waveform of the eight vulcanized tires is measured. Then, these waveforms are averaged to cancel the vulcanization factor and obtain the force variation average waveform of the green tire. Therefore, since there is a difference between the force variation average waveform of this green tire and the force variation waveform of each green tire that is actually vulcanized, the positive or negative maximum amplitude position of the force variation waveform of each green tire and the The force variation of the sulfur mold cannot be sufficiently offset with the negative or positive maximum amplitude position of the average waveform, and the force variation is not sufficiently reduced.

[0005]

SUMMARY OF THE INVENTION In consideration of the above facts, an object of the present invention is to obtain a method for manufacturing a radial tire capable of sufficiently reducing the force variation in the radial direction of each tire.

[0006]

According to a first aspect of the present invention, there is provided a method for manufacturing a radial tire according to the present invention, wherein an RRO waveform measuring step for measuring an RRO waveform of each green tire and a vulcanization factor waveform for each vulcanizer. The vulcanization factor waveform recording process of measuring and recording in the computer, and the RRO of the green tire by the computer
A selection step of selecting a combination of the circumferential position of the green tire and the circumferential position of the vulcanization mold that minimizes the RRO waveform amplitude of the vulcanized tire from the waveform and each vulcanization factor waveform;
The marking step of marking a predetermined position on the circumference of the green tire with respect to the circumferential reference position of the vulcanization mold selected in this selection step, and the marking position provided in this marking step and the reference position of the vulcanization mold are matched. A vulcanization step of placing a green tire in a vulcanization mold and vulcanizing it.

[0007]

In the radial tire manufacturing method according to the first aspect of the present invention, in the RRO waveform measuring step, the RRO waveform of the green tire to be vulcanized is measured by a laser displacement meter or the like and input to the computer. In the vulcanization factor waveform recording step, the vulcanization factor waveform is grasped in advance for each vulcanizer and recorded in the computer.
In the selection step, a combination of the circumferential position of the green tire and the circumferential position of the vulcanization mold that minimizes the RRO waveform amplitude of the vulcanized tire is selected by superimposing the RRO waveform of the green tire and each vulcanization factor waveform. . Furthermore, in the marking step, based on the selected combination of the circumferential positions, marking is performed on a predetermined position of the green tire with respect to the circumferential reference position of the vulcanization mold that minimizes the RRO waveform amplitude of the vulcanized tire. In the vulcanization step, the mark provided in the marking step is aligned with the reference position of the vulcanization mold, the green tire is placed in the vulcanization mold and vulcanized.

Therefore, the force variation in the radial direction can be sufficiently reduced.

[0009]

EXAMPLE A method of manufacturing a radial tire according to the present invention will be described with reference to FIGS.
It will be described with reference to FIG.

As shown in FIG. 1, in the RRO waveform measuring step, the molded green tire 10 is assembled to the wheel 12 fixed to the rotating shaft of the motor 11 and filled with a predetermined internal pressure. A well-known laser displacement meter 14 is fixed to a portion of the green tire 10 facing the tread portion 10A with its detection surface oriented toward the center of the green tire 10. The distance L from the tread portion 10A is measured by the total 14 and is input to the computer 16 to obtain the RRO waveform of the green tire as shown in FIG.

As shown in FIG. 3, in the vulcanization factor waveform recording step, four green tires 10 are placed in the vulcanization mold 20 of the vulcanizer 18, and four vulcanization tires 22A, 22 are provided.
B, 22C and 22D are vulcanized and molded. In this case, the four green tires 10 are arranged on the vulcanization mold 20 by rotating by 90 ° with respect to the reference position of the vulcanization mold 20, for example, the stencil position 20A.

Next, four vulcanized tires 22A, 22B,
The RRO waveforms of 22C and 22D are measured in the same manner as in the RRO waveform measuring step to obtain four RRO waveforms. When the RRO waveforms starting from these four stencil positions 20A are arithmetically processed by the computer 16 and averaged, the forming factors of the green tire 10 are offset, and the stencil positions 20A as shown in FIG. Vulcanizing mold 20 starting from
RRO waveform, that is, the vulcanization factor waveform is obtained. The vulcanization factor waveform of the vulcanization mold 20 is calculated by the computer 16 for each of the plurality of vulcanizers, and recorded in the storage element 16A.

In the selecting step, the RR in the computer 16 is
RR of green tire 10 collected in the O waveform measurement process
The O waveform (FIG. 2) and the vulcanization factor waveform (FIG. 4) of the vulcanization mold 20 starting from the reference position 20A recorded in the computer 16 in advance are overlapped, and one waveform is shifted in the circumferential direction. Then, by matching the positive maximum value of one waveform and the negative maximum value of the other waveform, the superposition position where the amplitude of the composite wave of both waveforms, that is, the RRO waveform of the vulcanized tire is minimized is selected.

In the marking step, the position of the green tire 10 with respect to the stencil position 20A of the vulcanization mold 20 is determined based on the position of superposition at which the amplitude of the RRO waveform of each vulcanized tire calculated in the selection step is minimized. That is, the overlapping angle θ is determined, and the marking device 26 marks the mark 28 at a predetermined position on the circumference of the green tire 10.

Specifically, in the selection step, the RRO waveform of a predetermined vulcanization mold 20 recorded in the computer 16 is called and this waveform and the RR of the green tire 10 measured separately.
When overlapping the O waveforms, the reference point of the vulcanization mold 20,
For example, starting from the stencil position 20A, a reference point of the green tire 10, for example, a tread joint position is shifted by an angle θ and overlapped to create several composite waveforms.

For example, the RRO waveform of the vulcanized tire when the overlapping angle θ is 0 ° is shown in FIG. 5A (amplitude W1), and the RR of the vulcanized tire when the overlapping angle θ is 33.5 °.
The O waveform is shown in FIG. 5 (B) (amplitude W2), and the RRO waveform of the vulcanized tire when the overlapping angle θ is 180 ° is shown in FIG. 5 (C).
(Amplitude W3), the vulcanized tire at the overlapping position when the maximum amplitude W3 of the RRO waveform of the vulcanized tire at the overlapping position where the angle θ is 180 ° is the former two angles. It was found that the maximum amplitude of the RRO waveform was smaller than W1 and W2, and the position where this angle θ was 180 ° was selected as the superposition position of the vulcanization mold 20 and the green tire 10, and the mark 28 was set at this position of the green tire 10. wear.

In the vulcanizing step, as shown in FIG. 1, the green tire 10 is rotated by the loader 30 and the mark 28 provided in the marking step is detected by the mark reading sensor 32 to detect the mark 28 and the vulcanizing mold 20. The green tire 10 is placed on the vulcanization mold 20 and vulcanized.

Therefore, in the radial tire manufacturing method of this embodiment, the RRO of each green tire 10 to be vulcanized is
The waveform is actually measured by the laser displacement meter 14, and the position of the RRO waveform amplitude of the vulcanized tire 22 is minimized with respect to the circumferential position of the vulcanizing mold 20 of the selected vulcanizer (for example, 18B). The green tire 10 can be positioned. For this reason, the force variation in the radial direction of the vulcanized tire 22 can be sufficiently reduced.

In this embodiment, the reference position of the vulcanization mold 20 is the stencil position 20A, but the reference position of the vulcanization mold is not limited to this, and other indications etc. are used as the reference position of the vulcanization mold. Is also good.

[0020]

The method for producing a radial tire of the present invention comprises:
RRO waveform measurement step of measuring the RRO waveform of each green tire, vulcanization factor waveform recording step of measuring the vulcanization factor waveform for each vulcanizer and recording it in a computer, and RRO waveform of the green tire by the computer And the respective vulcanization factor waveforms, a selection step of selecting a combination of the circumferential position of the green tire and the circumferential position of the vulcanization mold that minimizes the RRO waveform amplitude of the vulcanized tire, and the addition step selected in this selection step. Place the green tire on the vulcanization mold by combining the marking process of marking a predetermined position on the circumference of the green tire with respect to the circumferential reference position of the vulcanization mold and the marking position provided in this marking process and the reference position of the vulcanization mold. And vulcanization step of vulcanizing, it is possible to sufficiently reduce the radial force variation of each tire. Has an excellent effect that kill.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a method for manufacturing a radial tire according to an embodiment of the present invention.

FIG. 2 is an RRO waveform of a green tire of a method for manufacturing a radial tire according to an embodiment of the present invention.

FIG. 3 is a schematic explanatory view showing a step of extracting a vulcanization factor waveform in the radial tire manufacturing method according to the embodiment of the present invention.

FIG. 4 is a vulcanization factor waveform of a method for manufacturing a radial tire according to an embodiment of the present invention.

FIG. 5A is an RRO waveform of a vulcanized tire when the overlapping angle θ is 0 °, and FIG. 5B is the overlapping angle θ.
Is an RRO waveform of a vulcanized tire when is 33.5 °,
(C) is an RRO waveform of the vulcanized tire when the overlapping angle θ is 180 °.

[Explanation of symbols]

 10 Green Tire 14 Laser Displacement Meter 16 Computer 16A Storage Element 18 Vulcanizer 20 Vulcanizing Mold 20A Stencil 22 Vulcanizing Tire 26 Marking Device 28 Mark 30 Loader 32 Mark Reading Sensor

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Claims (1)

[Claims] 1. A RRO waveform measuring step of measuring an RRO waveform of each green tire, and a vulcanization factor waveform recording step of measuring a vulcanization factor waveform for each vulcanizer and recording it in a computer.
A selection step of selecting a combination of the circumferential position of the green tire and the circumferential position of the vulcanization mold that minimizes the RRO waveform amplitude of the vulcanized tire from the RRO waveform of the green tire and each vulcanization factor waveform by a computer; The marking step of marking a predetermined position on the circumference of the green tire with respect to the circumferential reference position of the vulcanization mold selected in this selection step, and the marking position provided in this marking step and the reference position of the vulcanization mold are matched. A vulcanization step of arranging a green tire in a vulcanization mold and vulcanizing the green tire.