JPH06182901A - Manufacture of green tire - Google Patents

Abstract

PURPOSE:To improve a manufacture of a pneumatic radial tire of when especially stated a divided segment improve in a tire-molding drum. CONSTITUTION:In a manufacturing process of a pneumatic radial tire, divided segments 11, 12 of a molding drum are divided unequally in a peripheral direction of the tire. At least three kinds of unequally dividing units of the divided segments 11, 12 of the molding drum are favorably provided. In molding the tire the segments 11, 12 of the molding drum are divided unequally in the peripheral direction of the tire thereby, and distortion generated in the tire can be dispersed thereby. The molding drum is adopted in any drum of, i.e., primary molding and secondary molding in molding of the radial tire, which scatters vibration of the tire, and provides the comfortable tire for an automobile-crew to drive.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method for manufacturing a pneumatic radial tire, and more particularly to an improved split segment in a tire building drum.

[0002]

2. Description of the Related Art In recent years, pneumatic tires have been almost of a radial structure, but a band molding for molding a tire ply and a first molding for molding a bead around the band obtained by this molding, It consists of a second molding in which a belt and a tread are set on a green case obtained by molding.
In band molding, the inner liner is placed on the innermost side of the band molding drum, and a nylon chafer, a wire chafer, etc. are wound around the inner liner, and then a hat rubber and a ply coat are wound on this. After setting these members, they are obtained by stitching. This is a band. In the first molding, the band is inserted on a first molding drum having a reduced diameter, the diameter is expanded to fix the band on the drum, and beads and side treads are added thereto. Is. The one obtained after this first molding is called a raw case. The drum for obtaining this raw case is divided into, for example, 12 pieces, and large and small segments are arranged every other row.

FIG. 1 shows a state in which a band forming drum and a first forming drum (hereinafter referred to as a drum, which will be described as a representative of the first forming drum) are expanded, and all the segments 1 and 2 are formed. They are arranged on the same circumference. Moreover, FIG.
Shows a state in which the diameter of the drum is reduced, the auxiliary segment 2 having a short length is moved to the center of the drum, and only the segment 1 forms the outer shape of the drum. In addition, segment 1,
Although 2 is shown as a curved surface, it may be a flat surface.

Further, in the second molding, in the O-ring molding, the belt and the tread are attached with the diameter of the drum expanded, and the diameter of the drum is reduced to move to the next molding step. The ring-shaped belt tread will be taken out. The segment of the second molded drum is usually constituted by the segments 3 having the same length. FIG. 3 shows a diameter expanded state and FIG. 4 shows a diameter reduced state.

[0005]

As described above, in the method for manufacturing a pneumatic radial tire, there are two steps for expanding and contracting the diameter of the drum, and therefore, for example, it corresponds to the segmented portion of the drum. The tire member thus stretched more than the members of other parts, and on the other hand, it is contracted unevenly. For this reason, the UN · that has an order component due to the number of segment divisions of this drum
UNIFORMITY tires will be manufactured. This means that when the tires are used for running, UN ・ U
This causes the tire to vibrate due to the running speed according to the degree of NIFORMITY.

[0006]

As a result of intensive studies to solve the above problems, the present invention has solved the problems by making the divided segments of the molding drum have the following constitution. . That is, the gist of the present invention is a method for manufacturing a green tire, characterized in that, in the process of manufacturing a pneumatic radial tire, the divided segments of the molding drum are unevenly divided in the tire circumferential direction, and preferably, A grease having at least three types of non-uniform division units of the divided segments of the molding drum.
The present invention relates to a manufacturing method of tires.

[0007]

According to the present invention, the division of the molding drum is made non-uniform, and the UN / U of the tire caused by the division order of the drum and its position.
The order component of NIFORMITY is dispersed to reduce the vibration component caused by this.

For example, in the case of using a molding drum in which the segments 1 (6 pieces) as shown in FIGS. 1 and 2 are divided into uniform lengths, the eccentricity of the tire corresponds to this segment 1. The order to do occurs mainly. Therefore, the degree of eccentricity also concentrates, and the ratio becomes large. Therefore, naturally, the vibration component also concentrates on such an order and becomes large, and a large vibration is given to the occupant.

However, in the case where the molding drum in which the segment 1 is dispersed in an inhomogeneous length as shown in FIG. . Therefore, the degree of eccentricity is dispersed, and the ratio is relatively small. Therefore, naturally, the vibration component is also dispersed in such an order, and the occupant does not feel the vibration.

In the division of the segment having such a purpose, it is preferable that the division unit of the segment is three or more, whereby the degree of eccentricity of the tire is dispersed,
The vibration to the occupant is reduced accordingly.

[0011]

EXAMPLES The present invention will now be described in more detail based on examples. FIG. 5 is a cross-sectional view of the molding drum in the first molding used for molding the radial tire, which is perpendicular to the drum axis line showing each segment at the time of expanding the diameter.
Is a sectional view when the diameter is reduced, and FIG. 7 is a partial sectional view parallel to the drum axis.

For example, the segment 11 is attached to the central shaft 21 by parallel links 22 and 23, and is further connected by a diameter-reducing link 24 to a collar 25 sliding on the central shaft 21. Therefore, color 25
Is moved to the left on the central shaft 21, the diameter of the segment 11 is expanded, and when the color 25 is moved to the right, the diameter reduction link 2
4 operates and the diameter of the segment 11 is reduced.

Molding drum segments 11, 12, 1
When the diameters of the components 3 and 14 are expanded, they all come into contact with each other to form a substantially perfect circle. Then, the segment 14 is an auxiliary segment, its width is smaller than that of the other segments, and it enters inside the other segments when the diameter is reduced. And segments 11, 12, 13
Are located at approximately 50, 60, and 70 degrees from the center. That is, the main segment of the molding drum of the present invention,
Two segments 11 corresponding to 50 degrees, two 60 degree segments 12 and two 70 degree segment 13 are distributed.

On the other hand, in the conventional molding drum, since the segment is composed of the segment 12 corresponding to 60 degrees and the auxiliary segment, the eccentricity (strain) of the tire is concentrated in the strain generated in the segment 12. However, in the present invention, this was dispersed, and the vibration component was reduced to about 1/3.

FIG. 8 is a graph showing a vibration component of a tire molded by such a conventional molding drum, in which the sixth-order component, that is, the strain in the segment 12 corresponding to 60 degrees, is concentratedly generated. .

On the other hand, FIG. 9 is a graph showing the vibration components of the tire molded by the molding drum of this invention.
Strains in the next component, the sixth component, the seventh component, that is, the segment 11 corresponding to 50 degrees, the segment 12 corresponding to 60 degrees, and the segment 13 corresponding to 70 degrees are collected in the tire. In other words, the tire is The strain generated in 3 is dispersed into three, and the vibration component thereof is smaller than that shown in FIG. 8 and is approximately 1/3.

FIG. 10 is a cross-sectional view of the molding drum in the second molding used for molding a radial tire at right angles to the drum axis line showing each segment at the time of diameter expansion, and FIG. FIG.

When the diameter of the segment is reduced, the six segments 21 that form an angle of 30 degrees from the center are
There are two segments 22 that form an angle of 2 degrees and two segments 23 that form an angle of 50 degrees. Therefore,
In the conventional molding drum, 12 segments 21
Eccentricity (distortion) of the tire due to this
In contrast to the above-mentioned segments, the segments were concentrated, but in the molding drum of the present invention, these were dispersed.

[0019]

According to the present invention, when a tire is molded, the segments of the molding drum are unevenly divided in the circumferential direction of the tire, whereby the strain generated in the tire can be dispersed. This molding drum is adopted for both so-called primary molding and secondary molding drums in the molding of radial tires, disperses tire vibrations, and provides a tire with a comfortable ride for passengers. It was decided.

[Brief description of drawings]

FIG. 1 shows each segment of a conventional molding drum (first molding) in an expanded state.

FIG. 2 shows each segment of the conventional molding drum (first molding) in a reduced diameter state.

FIG. 3 shows each segment of the conventional molding drum (second molding) in a diameter-expanded state.

FIG. 4 shows each segment of the conventional molding drum (second molding) in a reduced diameter state.

FIG. 5 is a cross-sectional view perpendicular to the drum axis showing each segment of the molding drum (first molding) of the present invention at the time of expanding the diameter.

FIG. 6 is a cross-sectional view perpendicular to the drum axis showing each segment of the molding drum (first molding) of the present invention when the diameter is reduced.

FIG. 7 is a partial cross-sectional view parallel to the drum axis of the molding drum (first molding) of the present invention.

FIG. 8 is a graph showing vibration components of a tire molded with a conventional molding drum.

FIG. 9 is a graph showing vibration components of a tire molded by the molding drum of the present invention.

FIG. 10 is a molding drum of the present invention (second molding).
FIG. 6 is a cross-sectional view showing each segment at the time of expanding the diameter at right angles to the drum axis.

FIG. 11 is a molding drum of the present invention (second molding).
FIG. 4 is a cross-sectional view showing each segment at the time of reducing the diameter, which is perpendicular to the drum axis.

[Explanation of symbols]

 11, 12, 13, 21, 22, 23 ... Segment, 14 ... Auxiliary segment, 21 ... Central shaft, 22, 23 ... Parallel link, 24 ... Reduced diameter link, 25 ... Sliding color.

Claims (2)

[Claims] 1. A method for producing a green tire, characterized in that, in a process of producing a pneumatic radial tire, divided segments of a molding drum are unevenly divided in a tire circumferential direction. 2. The method for producing a green tire according to claim 1, wherein at least three types of non-uniform division units of the division segment of the molding drum are provided.