JP7225589B2 - Tire molding drum device and tire manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a tire forming drum device capable of adjusting the width of a drum in the axial direction without forming a step on the outer peripheral surface of the drum, and a tire manufacturing method.

In a cylindrical drum for forming a green tire primary compact, it is necessary to adjust the width of the drum in the axial direction (sometimes referred to as drum width) according to the type and size of the tire. Therefore, the following Patent Documents 1 and 2 propose drums having an adjustable drum width. The proposed drum comprises a plurality of circumferentially arranged segments forming the outer circumference of the drum. Each segment is divided into a central segment piece and side segment pieces on either side.

In Patent Document 1, the axially outer end portion of the central segment piece and the axially inner end portion of the side segment piece are vertically overlapped, and the width of the overlap is changed to adjust the width of the drum. are doing.

In Patent Document 2, the axially outer end portion of the central segment piece and the axially inner end portion of the side segment piece are arranged to face each other, and the distance between the outer end portion and the inner end portion is changed. is used to adjust the width of the drum.

In either case, however, a step is generated on the outer peripheral surface of the drum due to the overlap of the ends (Patent Document 1) or due to the separation of the ends in the axial direction (Patent Document 2). Therefore, when a tire member (for example, a carcass ply) is wound along the outer peripheral surface of the drum, the carcass cord path (carcass cord length between bead cores) varies due to the step, and wrinkles occur in the tire member. Tend. This can cause deterioration of tire quality.

JP-A-59-202837 JP 2015-39821 A

SUMMARY OF THE INVENTION An object of the present invention is to provide a tire forming drum device and a tire manufacturing method capable of adjusting the drum width without providing a step on the outer peripheral surface of the drum.

A first invention of the present application is a tire forming drum device including a cylindrical drum to which a tire member is attached,
said drum comprising a plurality of circumferentially arranged segments whose radially outer surfaces cooperate with each other to define the outer peripheral surface of said drum;
Each of the segments is composed of a first segment piece and a second segment piece which are divided into two in the axial direction and supported so as to move toward each other relative to each other in the axial direction,
Each inner end portion of the first and second segment pieces in the axial direction has an uneven portion in which concave portions and convex portions are alternately arranged in the circumferential direction,
Moreover, the concave-convex portion of the first segment piece and the concave-convex portion of the second segment piece can mesh with each other.

In the tire building drum device according to the present invention, in each of the convex portions of the first and second segment pieces, the ridgeline where the side wall surfaces on both sides in the circumferential direction of the convex portion and the radial outer surface intersect is the axial center. It is preferable to extend along the direction.

In the tire building drum device according to the present invention, each of the protrusions of the first and second segment pieces has an axially inner end surface and a corner portion between the side wall surfaces on both sides in the circumferential direction of the protrusion. It is preferably chamfered by an arcuate surface with radius R of curvature.

In the tire building drum device according to the present invention, each of the first and second segment pieces moves radially inwards and outwards along a radial direction of movement passing through the center of the circumferential width of each segment piece,
In the first and second segment pieces,
Of the side wall surfaces on both sides in the circumferential direction of each convex portion, the side wall surface on the inner side in the circumferential direction, which is on the side of the center of the width, is wider than the reference surface in the radial direction extending from the ridge line toward the center of the side wall surface. Out of side wall surfaces on both sides in the circumferential direction of each convex portion, the side wall surface on the outer side in the circumferential direction passes on a reference plane in the radial direction extending from the ridgeline toward the center of the side wall surface. is preferred.

In the tire building drum device according to the present invention, it is preferable that the circumferentially inner side wall surface passes over the moving direction surface extending along the moving direction from the ridge line on the side wall surface.

In the tire building drum device according to the present invention, it is preferable that each of the first and second segment pieces has at least one or more grooves extending in the axial direction on the radially outer surface.

In the tire building drum device according to the present invention, it is preferable that the groove of the first segment piece and the groove of the second segment piece are arranged on a straight line.

In the tire building drum device according to the present invention, it is preferable that each of the first and second segment pieces includes a slide plate that is slidable in and out of the axial direction and fills the space of the recess.

A second invention of the present application is a tire manufacturing method including a step of forming a raw tire using the tire building drum apparatus of the first invention.

As described above, according to the present invention, the concave and convex portions formed on the inner ends of the first and second segment pieces in the axial direction can be engaged with each other.

Therefore, even when the drum width is adjusted by moving the first and second segment pieces toward and away from each other in the axial direction, the outer surface of the first segment piece and The outer surface of the second segment piece connects without a step.

Therefore, when the tire member is stuck on the outer peripheral surface of the drum, it is possible to suppress the unevenness of the carcass cord path and the occurrence of wrinkles in the tire member, thereby improving the tire quality.

It is a front view showing one embodiment of the drum in the tire building drum device of the present invention. FIG. 2 is a cross-sectional view taken in a direction perpendicular to the axis of the tire building drum device; FIG. 2 is an axial cross-sectional view of the tire building drum device; FIG. 4 is a plan view showing a state before first and second segment pieces are meshed; (A) and (B) are plan views showing the drum in a width-reduced state and a width-widened state. FIG. 11 is an enlarged plan view showing another example of the inner end portion of the convex portion; (A) and (B) are cross-sectional views in a direction perpendicular to the axis of an uneven portion of a first segment piece and an uneven portion of a second segment piece. (A) and (B) are a cross-sectional view and a bottom view showing another embodiment of the first and second segment pieces, representing the second segment piece.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.
As shown in FIG. 1 , the tire building drum device 1 of this embodiment includes a cylindrical drum 3 rotatably supported by a central shaft 2 . By successively attaching the tire members A on the outer peripheral surface 3S of the drum 3, in this example, a cylindrical primary molded body (not shown) before shaping is formed.

Examples of the tire member A include inner liner rubber, carcass ply, chafer rubber, bead core, bead apex rubber, and sidewall rubber.

As shown in FIG. 2, the drum 3 comprises a plurality of (for example, six) segments 5 circumferentially arranged around the central axis 2, and radial movement means 6 for moving each segment 5 radially inwards and outwards. Equipped with Each segment 5 moves radially outward, so that the drum 3 is in the expanded state Y1, and the radial outer surface 5S of each segment 5 cooperates with each other to form a cylindrical outer peripheral surface 3S. Further, each segment 5 is moved radially inward, so that the drum 3 is brought into a diameter-reduced state Y2, and the primary formed body formed by the outer peripheral surface 3S is removed from the drum 3. As shown in FIG.

The segment 5 is composed of two types of large and small segments 5A and 5B arranged alternately in the circumferential direction. A circumferential end surface Fa of the segment 5A is inclined in a direction in which the circumferential width decreases radially inward. On the other hand, the circumferential end face Fb of the segment 5B is inclined so that the circumferential width increases radially inward. The radial movement distance of the segment 5B from the expanded state Y1 to the reduced diameter state Y2 is greater than the radial movement distance of the segment 5A.

As shown in FIGS. 1 and 3, each segment 5 is composed of first and second segment pieces 9L and 9R divided in the axial direction. The first and second segment pieces 9L and 9R are supported by an axial movement means 10 so as to be relatively movable toward and away from each other in the axial direction. In this specification, the direction in which the first and second segment pieces 9L and 9R approach is axially inward, and the direction away from them is axially outward. This example shows the case where the first and second segment pieces 9L and 9R move inward and outward in the axial direction around the central position Co. However, if required, one of the first and second segment pieces 9L, 9R can be fixed and only the other can be moved in and out in the axial direction.

As shown in FIGS. 2 and 3, in this example, the radial direction moving means 6 includes a cylinder 12 radially attached to the central shaft 2 via a pedestal portion 11, and a rod end of the cylinder 12, which moves in parallel in the radial direction. and a possible moving platform 13 . A link mechanism may be employed instead of the cylinder 12 . The moving table 13 of this example includes plate-like portions 13i and 13o arranged radially inside and outside and extending in the axial direction.

The axial movement means 10 includes a screw shaft 15 supported on the moving table 13 parallel to the central axis 2, and a connecting piece 16L connecting the first and second segment pieces 9L, 9R and the screw shaft 15, respectively. , 16R.

Both ends of the screw shaft 15 are rotatably supported on the moving table 13 . Threaded portions 15L (for example, left-handed thread) and 15R (for example, right-handed thread) are formed in different directions on one side and the other side of the screw shaft 15 in the axial direction. Further, the central portion of the screw shaft 15 is connected to a motor M fixed to the moving table 13 by a gear connecting means 20, for example.

The connecting piece 16L includes a block portion 17L fixed to the radially inner surface of the first segment piece 9L, a nut portion 18L screwed onto the threaded portion 15L, and a joint portion 19L connecting the block portion 17L and the nut portion 18L. I get it. The connecting piece 16R includes a block portion 17R fixed to the radially inner surface of the second segment piece 9R, a nut portion 18R screwed onto the threaded portion 15R, and a joint portion 19R connecting the block portion 17R and the nut portion 18R. equip.

The outer plate-shaped portion 13o of the moving table 13 is provided with guide holes 21L and 21R for guiding the joint portions 19L and 19R so as to be movable in the axial direction.

Therefore, the first and second segment pieces 9L and 9R can move closer to each other around the central position Co by controlling the rotation of the motor M. As shown in FIG.

As shown in FIG. 4, the inner end portion of the first segment piece 9L in the axial direction is provided with a comb-like uneven portion 24L in which concave portions 22L and convex portions 23L are alternately arranged in the circumferential direction. . Similarly, the inner end portion of the second segment piece 9R in the axial direction has a comb-tooth-like uneven portion 24R in which concave portions 22R and convex portions 23R are alternately arranged in the circumferential direction.

In the uneven portions 24L and 24R, portions protruding inward in the axial direction are defined as the convex portions 23L and 23R, the portion between the convex portions 23L and 23L is defined as the concave portion 22L, and the portion between the convex portions 23R and 23R is defined as the concave portion 22R. be done.

The concave-convex portion 24L and the concave-convex portion 24R are formed so as to be able to mesh with each other. That is, the concave portion 22L and the convex portion 23R face each other in the axial direction, and the convex portion 23R is formed in the concave portion 22L so as to be insertable in the axial direction. Similarly, the concave portion 22R and the convex portion 23L face each other in the axial direction, and the convex portion 23L is formed in the concave portion 22R so as to be insertable in the axial direction. Further, in the convex portions 23L and 23R, ridgelines J where the side wall surfaces S on both sides in the circumferential direction of the convex portions 23L and 23R and the radial outer surface 5S intersect each extend along the axial direction.

In this example, each of the uneven portion 24L and the uneven portion 24R has a rectangular wave shape in which the unevenness is repeated at a constant cycle in the circumferential direction. The circumferential width Wa of the concave portions 22L and 22R on the radial outer surface 5S is larger than the circumferential width Wb of the convex portions 23L and 23R on the radial outer surface 5S, and the difference (Wa-Wb) is 1 to 3 mm. is preferred.

Therefore, as shown in FIG. 5(A), the concave-convex portion 24L and the concave-convex portion 24R are deeply meshed with each other, and from the reduced width state Q1 in which the drum width W2 is minimized, the concave-convex portion 24L and the uneven portion 24R are shallowly meshed and the drum is The drum width W2 can be freely adjusted up to the widening state Q2 where the width W2 is maximized.

Also in the widened state Q2, the engagement state is maintained, so that the inner end portion of the convex portion 23L and the inner end portion of the convex portion 23R are adjacent to each other in the circumferential direction, and the annular portion 25 is substantially continuous in the circumferential direction. is formed.

The annular portion 25 allows the outer surface 5S of the first segment piece 9L and the outer surface 5S of the second segment piece 9R to be connected substantially without a step. As a result, when the tire member A is attached on the outer peripheral surface 3S of the drum 3, it is possible to prevent the carcass cord path from becoming uneven and the tire member A from wrinkling.

As shown in FIG. 5A, in the contracted width state Q1, the axial gap G between the convex portion 23L and the concave portion 22R and the axial gap G between the convex portion 23R and the concave portion 22L is preferably in the range of 3-7 mm. Further, as shown in FIG. 5(B), in the widened state Q2, the width W25 of the annular portion 25 in the axial direction is preferably 10 mm or more.

As shown in FIG. 6, in the concave and convex portions 24L and 24R, the respective convex portions 23L and 23R are corner portions between the inner end surfaces Es of the convex portions 23L and 23R in the axial direction and the side wall surfaces S on both sides in the circumferential direction. 27 is preferably chamfered by an arcuate surface 28 of radius R of curvature. This can prevent the corner portions 27, 27 from colliding with each other when the uneven portions 24L, 24R are meshed with each other, and the meshing operation can be facilitated. Therefore, the radius of curvature R is preferably in the range of 3-9 mm.

FIG. 7 shows a sectional view perpendicular to the axial center of the uneven portion 24L of the first segment piece 9L and a sectional view perpendicular to the axial center of the uneven portion 24R of the second segment piece 9R. Note that the first and second segment pieces 9L and 9R are respectively moved in the radial direction passing through the circumferential width center cw of each segment piece 9L and 9R by the radial movement means 6 (shown in FIG. 2). Move radially in and out along K.

In the first segment piece 9L, of the side wall surfaces S on both sides in the circumferential direction of the convex portion 23L, the side wall surface Si on the inner side in the circumferential direction, which is on the width center cw side, Circumferentially outside the radial reference plane Xs extending toward . On the other hand, the circumferentially outer side wall surface So passes on the radial reference plane Xs extending from the ridgeline J of the side wall surface So toward the axial center.

Similarly, in the second segment piece 9R, of the side wall surfaces S on both sides in the circumferential direction of the protrusion 23R, the side wall surface Si on the inner side in the circumferential direction, which is on the side of the width center cw, is aligned with the ridge line J on this side wall surface Si. passes through the outer side in the circumferential direction of the radial reference plane Xs extending from to the axial center. On the other hand, the circumferentially outer side wall surface So passes on the radial reference plane Xs extending from the ridgeline J of the side wall surface So toward the axial center.

In FIG. 7, the first and second segment pieces 9L and 9R of the segment 5B are representatively shown, but the first and second segment pieces 9L and 9R of the segment 5A also The side wall surface Si passes on the outer side in the circumferential direction of the reference plane Xs, and the side wall surface Si on the outer side in the circumferential direction passes on the reference plane Xs.

Here, when the diameter of the segment 5 is expanded and contracted, there is a difference between the timing of radially inward and outward movement of the first segment piece 9L and the timing of radial inward and outward movement of the second segment piece 9R. In such a case, the projection 23L and the recess 22R and/or the projection 23R and the recess 22L may interfere and lock. On the other hand, the locking can be suppressed by setting the side wall surface Si on the inner side in the circumferential direction to the outer side in the circumferential direction with respect to the reference surface Xs. In particular, it is more preferable for the circumferentially inner side wall surface Si to pass over the movement direction surface Ks extending along the movement direction K from the ridgeline J in order to avoid locking.

As shown in FIG. 4, in this example, at least one groove 26 extending in the axial direction is arranged on the outer surface 5S of the first and second segment pieces 9L and 9R. The grooves 26 are exhaust grooves, and when the tire member A is directly adhered to the outer peripheral surface 3S, air trapped between the outer peripheral surface 3S and the tire member A can be discharged outside the drum.

Depending on the number of segments 5, it is preferable to form 2 to 3 grooves 26 in the segment 5A and to form 1 to 2 grooves 26 in the segment 5B. The groove 26 preferably has a depth of 0.5 to 1.5 mm and a width of 3 to 5 mm. One end of the groove 26 extends to the inner ends of the uneven portions 24L and 24R.

The grooves 26 of the first segment piece 9L and the grooves 26 of the second segment piece 9R are preferably arranged on a straight line for exhaust.

8(A) and (B) show another embodiment of the first and second segment pieces 9L and 9R. In the figure, the second segment piece 9R is representatively shown. In the segment piece 9R, a slide plate 30 filling the space H of the recess 22R is arranged in each recess 22R so as to be slidable in and out in the axial direction. The slide plate 30 of this example is slidably held in a housing chamber 31 provided in the segment piece 9R. The slide plate 30 is urged inward in the axial direction by a spring means 34 arranged in the housing chamber 31 . A reference numeral 32 denotes a stopper projecting radially inward from the slide plate 30 and passing through a guide hole 33 provided in the segment piece 9R. As a result, the slide plate 30 is retained at the reference position P where the axially inner end of the slide plate 30 and the axially inner end of the projection 23R are substantially aligned.

Also in each recess 22L of the first segment piece 9L, a slide plate 30 that fills the space H of the recess 22L is arranged with the same structure.

When the uneven portions 24L and 24R mesh with each other, the slide plate 30 can be pushed outward in the axial direction by being pushed by the convex portions 23L and 23R, respectively. As a result, the slide plate 30 can fill the space H of the recess 22R and the space H of the recess 22R without being affected by the meshing state. In this case, the attachment accuracy of the tire member A can be further improved. Also, the occurrence of air pockets between the drum 3 and the tire member A can be further suppressed.

Next, the tire manufacturing method includes the step of forming a raw tire using the tire forming drum device 1 .

The tire forming drum device 1 can be used to form a cylindrical 1st cover before the tread ring is joined in a green tire, or can be used to form a separately formed cylindrical carcass when forming the 1st cover. It can also be used to attach sidewall rubber to

When forming the 1st cover using the tire forming drum device 1, as an example,
(a) The width of the drum 3 is adjusted according to the size of the tire to be formed, and then the inner liner and the carcass ply are sequentially wound on the drum 3 to form a cylindrical wound body.
(a) After that, a bead core is set on the outer end of the wound body in the axial direction of the tire, and the part of the wound body that protrudes axially outward from the bead core is folded back around the bead core. to form a cylindrical carcass containing the bead core.
(c) After that, sidewall rubber is attached onto the cylindrical carcass to form the 1st cover.

When the tire forming drum device 1 is used to attach the sidewall rubber to a separately formed cylindrical carcass, as an example,
(A) A former for forming a cylindrical carcass is used, and a cylindrical wound body and a cylindrical carcass are sequentially formed on this former in the same manner as in (A) and (B) above.
(B) After that, the cylindrical carcass is taken out from the former and mounted on the drum 3 . This mounting can be performed by adjusting the diameter of the drum 3 and the width of the drum.
(C) Thereafter, sidewall rubber is attached onto the cylindrical carcass to form the 1st cover.

When a raw tire is formed using the tire forming drum apparatus 1, traces of the interlocking uneven portions 24L and 24R remain on the inner cavity surface of the product tire. Therefore, it is possible to distinguish it from other tires.

Although the particularly preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the illustrated embodiments and can be modified in various ways.

1 tire building drum device 3 drum 3S outer peripheral surface 5, 5A, 5B segment 5S outer surface 9L first segment piece 9R second segment piece 22L, 22R concave portions 23L, 23R convex portions 24L, 24R uneven portion 26 groove 27 corner Part 28 Circular surface 30 Slide plate A Tire member cw Width center Es Inner end surface H Space J Ridgeline J
K moving direction Ks moving direction surface S, Si, So side wall surface Xs reference surface

Claims (8)

A tire building drum apparatus including a cylindrical drum to which a tire member is attached,
said drum comprising a plurality of circumferentially arranged segments whose radially outer surfaces cooperate with each other to define the outer peripheral surface of said drum;
Each segment is divided into two pieces in the axial direction and is composed of a first segment piece and a second segment piece that are supported so as to be relatively movable toward each other in the axial direction,
Each inner end portion of the first and second segment pieces in the axial direction has an uneven portion in which concave portions and convex portions are alternately arranged in the circumferential direction,
The uneven portion of the first segment piece and the uneven portion of the second segment piece can be engaged with each other,
Each of the projections of the first and second segment pieces is chamfered with an arcuate surface having a radius of curvature R at the corners of the inner end surface of the projection in the axial direction and the side wall surfaces on both sides in the circumferential direction. cage,
In each of the protrusions of the first and second segment pieces, a ridge line where the side wall surfaces on both sides in the circumferential direction of the protrusion intersect with the radial outer surface extends along the axial direction,
each of the first and second segment pieces moves radially inwards and outwards along a radial direction of movement passing through the center of the circumferential width of each segment piece;
In the first and second segment pieces,
Of the side wall surfaces on both sides in the circumferential direction of each convex portion, the side wall surface on the inner side in the circumferential direction, which is on the side of the center of the width, is wider than the reference surface in the radial direction extending from the ridge line toward the center of the side wall surface. through the direction outside, and
Of the side wall surfaces on both sides in the circumferential direction of each of the protrusions, the side wall surface on the outer side in the circumferential direction passes on a reference plane in the radial direction extending from the ridge line toward the center of the side wall surface.
Tire building drum equipment. 2. The tire building drum device according to claim 1, wherein the circumferentially inner side wall surface passes over a moving direction surface extending along the moving direction from the ridge line on the side wall surface. 3. A tire building drum apparatus according to claim 1 or 2, wherein each of said first and second segment pieces has at least one axially extending groove on said radially outer surface. 4. A tire building drum apparatus according to claim 3, wherein said grooves of said first segment piece and said grooves of said second segment piece are arranged on a straight line. The tire building drum device according to any one of claims 1 to 4, wherein each of said first and second segment pieces includes a slide plate which is slidable in and out of the axial direction in each of said recesses and fills a space of said recess. . A tire building drum apparatus including a cylindrical drum to which a tire member is attached,
said drum comprising a plurality of circumferentially arranged segments whose radially outer surfaces cooperate with each other to define the outer peripheral surface of said drum;
Each segment is divided into two pieces in the axial direction and is composed of a first segment piece and a second segment piece that are supported so as to be relatively movable toward each other in the axial direction,
Each inner end portion of the first and second segment pieces in the axial direction has an uneven portion in which concave portions and convex portions are alternately arranged in the circumferential direction,
The uneven portion of the first segment piece and the uneven portion of the second segment piece can be engaged with each other,
A tire building drum apparatus as claimed in claim 1, wherein said first and second segment pieces each include at least one axially extending groove on said radially outer surface. A tire building drum apparatus including a cylindrical drum to which a tire member is attached,
said drum comprising a plurality of circumferentially arranged segments whose radially outer surfaces cooperate with each other to define the outer peripheral surface of said drum;
Each segment is divided into two pieces in the axial direction and is composed of a first segment piece and a second segment piece that are supported so as to be relatively movable toward each other in the axial direction,
Each inner end portion of the first and second segment pieces in the axial direction has an uneven portion in which concave portions and convex portions are alternately arranged in the circumferential direction,
The uneven portion of the first segment piece and the uneven portion of the second segment piece can be engaged with each other,
A tire building drum device in which the first and second segment pieces each include a slide plate that is slidable in and out of the axial direction and fills the space of the recess in each of the recesses. A tire manufacturing method comprising the step of forming a green tire using the tire building drum apparatus according to any one of claims 1 to 7.

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