JP2024042782A - Manufacturing method and apparatus for pneumatic tire - Google Patents

Abstract

To provide a method and apparatus for manufacturing a pneumatic tire that can reduce an occurrence of defects during molding by appropriately calculating a clearance between chucks that hold bead parts.SOLUTION: A method for manufacturing a pneumatic tire includes: producing a first case body having a pair of bead parts; generating a second case body including a belt; calculating a first distance in a tire axial direction from an outer edge of the belt to an inner edge of the bead part based on a rise height along a tire radial direction from an inner end of the bead part to an outer end of the belt when the first case body and the second case body are integrated and a rise angle from the inner end of the bead part to the outer end of the belt; calculating a second distance by adding the first distance to an axial dimension of the belt from both ends of the belt in the tire axial direction toward an outside in the tire axial direction; and reducing a clearance along the tire axial direction between the bead parts held by a pair of chucks to the second distance while inflating the first case body, and unifying the first case body and the second case body.SELECTED DRAWING: Figure 7

Description

The present disclosure relates to a method and apparatus for manufacturing a pneumatic tire.

A pneumatic tire is made by integrating a first case body in which multiple tire components such as a carcass are molded, and a second case body in which multiple tire components such as tread rubber and belts are molded into one green tire (green tire). The green tire is then manufactured by heating and pressurizing the green tire in a mold to vulcanize it (see Patent Document 1).

JP 2021-41666 A

As shown in FIG. 9, a process of forming the first case body T1 and the second case body T2 into one green tire will be described. With the second case body T2 located outside the first case body T1 in the tire radial direction RD, the bead portion 1 of the first case body T1 is held by a pair of chucks 510 of the molding device. The distance between the bead portions 1 before inflation is the initial distance L3. Next, while the first case body T1 is inflated, the pair of chucks 510 approach each other until the distance between the bead parts 1 becomes the second distance L2, and the first case body T1 and the second case body T2 are integrated. be converted into Thereafter, while the integrated first case body T1 and second case body T2 are held by a pair of chucks 510, sidewall rubber may be attached.

As shown in FIG. 9, the second distance L2 was determined such that the initial distance L3 coincides with half the circumference of a circle having the second distance L2 as a diameter. In this case, the second distance L2 may become smaller than the tire axial dimension L0 of the belt 6 along the tire axial direction AD. In this case, the inflated first case body T1 and second case body T2 have no firmness and tend to wobble, and the bead portion 1 of the integrated first case body T1 comes off the chuck 510, causing the molding process to be delayed. Problems such as stopping may occur.

This disclosure provides a method and device for manufacturing a pneumatic tire that can reduce the occurrence of defects during molding by appropriately calculating the separation distance of the chucks that hold the bead portion.

A method for manufacturing a pneumatic tire according to the present disclosure includes winding a plurality of tire members including an inner liner and a carcass around a carcass band drum to produce a cylindrical first case body having a pair of bead portions, Wrapping a plurality of tire members including a belt around a belt drum to generate a cylindrical second case body; and an inner end of the bead portion in a state where the first case body and the second case body are integrated. Based on the rising height along the tire radial direction from the outer end of the belt to the outer end of the belt and the rising angle from the inner end of the bead part to the outer end of the belt, by calculating a first distance in the tire axial direction from both ends of the belt in the tire axial direction, and adding each of the first distances to the tire axial dimension of the belt from both ends of the belt in the tire axial direction to the outside in the tire axial direction. calculating a second distance; and while inflating the first case body while holding the pair of bead portions of the first case body with a pair of chucks, the bead portions held by the pair of chucks are connected to each other. reducing a separation distance along the tire axial direction to a second distance, and integrating the first case body and the second case body.

The pneumatic tire manufacturing apparatus of the present disclosure includes a carcass band drum around which a plurality of tire members including an inner liner and a carcass are wound to produce a cylindrical first case body having a pair of bead portions; a belt drum around which a plurality of tire members including a belt are wound to produce a cylindrical second case body, the pair of bead portions of the first case body being held by respective pairs of chucks; , while inflating the first case body, the separation distance of the pair of chucks along the tire axial direction is reduced to a second distance, and the first case body and the second case body are integrated. and the rising height along the tire radial direction from the inner end of the bead part to the outer end of the belt when the first case body and the second case body are integrated, and the inner end of the bead part. A first distance in the axial direction of the tire from the outer end of the belt to the inner end of the bead portion is calculated based on the rising angle from both ends of the belt in the axial direction of the tire. The second distance is calculated by respectively adding the first distance to the tire axial dimension of the belt toward the outside in the axial direction.

FIG. 1 is a tire meridian cross-sectional view schematically showing the structure of a green tire. The figure which shows the molding process of a 1st case body. The figure which shows the operation of each device which constitutes a manufacturing system of a pneumatic tire. The figure which shows the molding process of a 2nd case body. Explanatory diagram regarding the process of integrating the first case body and the second case body. Explanatory diagram regarding the process of integrating the first case body and the second case body. FIG. 7 is an explanatory diagram regarding a method for determining a second distance. FIG. 7 is an explanatory diagram regarding a method for determining a second distance. FIG. 6 is an explanatory diagram regarding a conventional method for determining a second distance.

Hereinafter, a first embodiment of the present disclosure will be described with reference to the drawings.

[Structure of green tire T3 (green tire)]
FIG. 1 is a tire meridian cross-sectional view schematically showing the structure of a green tire T3. In the figure, in order to facilitate understanding, gaps are provided between some tire members. As shown in FIG. 1, the green tire T3 includes a pair of bead portions 1, a sidewall 2 extending from each bead portion 1 to an outer side RD1 in the tire radial direction, and the ends of the outer RD1 in the tire radial direction of the sidewall 2 are connected to each other. The tread 3 is provided. Arranged in the bead portion 1 are an annular bead core 1a made of a convergent body such as a steel wire coated with rubber, a bead filler 1b made of hard rubber, and a chafer 1c covering the bead core 1a. Further, the green tire T3 includes a toroidal carcass 4 which is disposed so as to span between a pair of bead portions 1 and extends from the tread 3 through the sidewall 2 to the bead portion 1. At least one carcass 4 is provided, and the end portion of the carcass 4 is locked in a rolled up state via the bead core 1a. An inner liner 5 for maintaining air pressure is arranged on the inner peripheral side of the carcass 4. A plurality of (two in this embodiment) belts 6 are arranged around the outer periphery of the carcass 4 in the tread 3 to reinforce the carcass 4 through a hoop effect. Each of the plurality of belts 6 has a metal cord extending at a predetermined angle with respect to the tire circumferential direction. The plurality of belts 6 are stacked such that the metal cords intersect with each other in opposite directions. A belt reinforcing layer 7 having non-metallic cords such as resin cords is disposed on the outer circumferential side of the plurality of belts 6, and tread rubber 8 is further disposed on the outer circumferential surface thereof. On the outer periphery of the carcass 4 in the sidewall 2, sidewall rubber 9 forming the tire side surface is arranged.

[Manufacturing method of pneumatic tires]
The method for manufacturing a pneumatic tire includes a step of laminating a plurality of tire members to manufacture a green tire T3, and a step of vulcanizing and molding the green tire T3 by heating and pressurizing it in a mold. The manufacturing method of the green tire T3 includes a step of molding a first case body T1 also called a first case, a step of molding a second case body T2 also called a second case, and a step of inflating the first case body T1 to form a second case body T1. A step of combining with the case body T2 to obtain a green tire T3 is included.

[Molding of first case body T1 (first case)]
The process of molding the first case body T1 will be explained using FIG. 2. FIG. 2 is a diagram showing the molding process of the first case body T1. As shown in FIG. 2, the inner liner 5, the chafer 1c, and the carcass 4 are wound around the carcass band drum 50. Thereafter, a bead filler 1b and a bead core 1a are placed at both ends of the carcass 4, and the first case body T1 is formed. In some cases, all or part of the sidewall rubber 9 is integrated. As shown in FIG. 3, the molded first case body T1 is transported from the carcass band drum 50 to a molding device 51 (also called a shaving drum) by a carcass transfer 52. FIG. 3 is a diagram showing the operation of each device constituting the pneumatic tire manufacturing system.

[Molding of second case body T2 (second case)]
The process of molding the second case body T2 will be explained using FIG. 4. FIG. 4 is a diagram showing the molding process of the second case body T2. As shown in FIG. 4, after the belt 6 and the belt reinforcing layer 7 (not shown in the figure) are wound around the belt drum 53, the tread rubber 8 is wound around the tire to obtain the second case body T2. The molded second case body T2 is conveyed from the belt drum 53 to the molding device 51 by a belt transfer 54, as shown in FIG.

[Combination of first case body T1 and second case body T2]
5 and 6 are explanatory diagrams regarding the process of integrating the first case body T1 and the second case body T2. As shown in FIG. 5, the pair of chucks 510 of the molding device 51 hold the bead portions 1 of the first case body T1, and the separation distance between the bead portions 1 held by the pair of chucks 510 is an initial distance. It is set to L3. The distance between the bead portions 1 is the distance along the tire axial direction AD between the inner ends P2 (see FIG. 7, inner ends in the tire radial direction and inner ends in the tire axial direction) of the bead portions 1. The initial distance L3 is set according to the distance between the bead portions 1 of the first case body T1 before inflation. The second case body T2 is held by the belt transfer 54, and is arranged with the tire equatorial plane aligned with the tire radial direction outer side RD1 of the first case body T1.

Next, the carcass 4 of the first case body T1 is rolled up using a turn-up bladder (not shown), and as shown in FIG. The separation distance between the tires along the tire axial direction AD is reduced to a second distance L2. Next, the second case body T2 is pressed against the first case body T1 using a stitcher (not shown) to join the second case body T2 and the first case body T1 to form a green tire T3. In this embodiment, although not shown, the sidewall rubber 9 is attached after the first case body T1 and the second case body T2 are integrated.

In the above process, the second distance L2 is determined as follows. Figures 7 and 8 are explanatory diagrams of a method for determining the second distance L2. As shown in Figures 7 and 8, a rise height H1 along the tire radial direction RD from the inner end P2 of the bead portion 1 to the outer end P1 of the belt 6 (the outermost end of the belt 6 in the tire axial direction AD) in a state in which the first case body T1 and the second case body T2 are integrated is specified. The rise height H1 can be calculated based on the diameter φ1 of the belt drum 53 and the diameter φ2 of the carcass band drum 50. Specifically, it can be calculated by the diameter difference between the belt drum 53 and the carcass band drum 50, that is, H1 = (φ1 - φ2) / 2. In this embodiment, the belt 6 that is the specification standard for the rise height H1 is the first belt (counted as the first, second, etc. from the inside to the outside in the tire radial direction RD), but is not limited to the first belt. For example, the belt 6 that has the longest tire axial length among multiple belts 6 having metal cords is the target. The same applies to the belt 6 that is the specification standard for the rise angle θ described later.

Further, the rising angle θ from the inner end P2 of the bead portion 1 toward the outer end P1 of the belt 6 is specified. The rising angle θ can be calculated based on the tire cross-sectional height after tire vulcanization. The tire cross-sectional height after tire vulcanization is approximately the same as the tire cross-sectional height of green tire T3 before tire vulcanization, so it can be used. Specifically, the memory of the molding device 51 stores a plurality of pieces of data in which the tire cross-sectional height and the rising angle θ are associated with each other. For example, a tire cross-sectional height of less than 100 mm is associated with a rising angle θ of 85 degrees, and a tire cross-sectional height of 100 mm or more and less than 120 mm is associated with a rising angle θ of 80 degrees. , it is associated that the rising angle θ is 75 degrees when the tire cross-sectional height is 120 mm or more and 140 mm or less. The forming device 51 specifies the rising angle θ corresponding to the tire cross-sectional height specified by the user based on a plurality of data.

Next, a first distance L1 in the tire axial direction AD from the outer end P1 of the belt 6 to the inner end P2 of the bead portion 1 is calculated based on the rising height H1 and the rising angle θ. The first distance L1 can be calculated as L1=H1/tanθ.

Next, a second distance L2 is calculated by adding the first distance L1 to the tire axial dimension L0 of the belt 6 from both ends of the belt 6 in the tire axial direction AD toward the outside in the tire axial direction. That is, L2=L0+L1×2. This makes it possible to calculate an appropriate second distance L2.

[Modified example]
(A) In the above embodiment, the sidewall rubber 9 is attached after the first case body T1 and the second case body T2 are integrated, but the invention is not limited to this. All or part of the sidewall rubber 9 may be attached to the first case body T1 in advance.

(B) The tires of the above embodiments are for passenger cars, but are not limited thereto. For example, it may be for a light truck (LT).

[1]
As described above, the method for manufacturing a pneumatic tire involves winding a plurality of tire members including the inner liner 5 and the carcass 4 around the carcass band drum 50 to produce the cylindrical first case body T1 having the paired bead portions 1. and winding a plurality of tire members including the tread rubber 8 and the belt 6 around the belt drum 53 to generate a cylindrical second case body T2, and forming the first case body T1 and the second case body T2. The rising height H1 along the tire radial direction RD from the inner end P2 of the bead part 1 to the outer end P1 of the belt 6 in the integrated state and the rising height H1 from the inner end P2 of the bead part 1 to the outer end P1 of the belt 6 The first distance L1 in the tire axial direction AD from the outer end P1 of the belt 6 to the inner end P2 of the bead portion 1 is calculated based on the angle θ, and both ends (P1, P1) toward the outside in the tire axial direction AD, the second distance L2 is calculated by adding the first distance L1 to the tire axial direction dimension L0 of the belt 6, and the pair of beads of the first case body T1 While inflating the first case body T1 with each of the bead parts 1 held by the pair of chucks 510, the separation distance along the tire axial direction AD between the bead parts 1 held by the pair of chucks 510 is set to a second distance L2. It may also include shrinking and integrating the first case body T1 and the second case body T2.

In this way, the second distance L2, which is the separation distance between the inner ends of the bead portions 1, is the first distance L1 from both ends (P1, P1) of the belt 6 in the tire axial direction AD toward the outside in the tire axial direction AD. It is added. Therefore, the wobbling of the green tire T3 can be suppressed, and the occurrence of problems due to the wobbling can be suppressed.

[2]
In the method for manufacturing a pneumatic tire described in [1] above, the rising height H1 is calculated based on the diameter difference between the carcass band drum 50 and the belt drum 53, and the rising angle θ is the tire cross-sectional height after tire vulcanization. It may be calculated based on the
In this way, the value is calculated based on the specifications of the tire after vulcanization (tire cross-sectional height) and the manufacturing conditions of the manufacturing equipment (diameter difference between carcass band drum 50 and belt drum 53) tailored to the tire after vulcanization. This makes it possible to uniformly determine the second distance L2.

[3]
In the method for manufacturing a pneumatic tire described in [2] above, the rising angle θ corresponding to the specified tire cross-sectional height is specified based on a plurality of data that associates the rising angle θ with the tire cross-sectional height, and the specified The first distance L1 may be calculated using the rising angle θ.
In this way, it becomes possible to accommodate multiple types of tire sizes.

[4]
In the method for manufacturing a pneumatic tire according to [3] above, when the tire cross-sectional height is 99 mm or less, the rising angle θ is 85 degrees, and when the tire cross-sectional height is 100 mm or more and 119 mm or less, It is also possible to associate that the rising angle θ is 80 degrees, and to associate the rising angle θ of 75 degrees with a tire cross-sectional height of 120 mm or more and 140 mm or less. This is a preferable example.

[5]
The pneumatic tire manufacturing apparatus of this embodiment includes a carcass band drum around which a plurality of tire members including an inner liner 5 and a carcass 4 are wound to produce a cylindrical first case body T1 having a pair of bead portions 1. 50, and a belt drum 53 around which a plurality of tire members including tread rubber 8 and belt 6 are wound to produce a cylindrical second case body T2, and a pair of bead portions 1 of the first case body T1. are held by the pair of chucks 510, while inflating the first case body T1, the distance between the pair of chucks 510 along the tire axial direction AD is shortened to the second distance L2, and the first case body T1 and the first case body T1 are held together by the pair of chucks 510. The belt 6 is configured to integrate the two case bodies T2 from the inner end P2 of the bead portion 1 to the outer end P1 of the belt 6 when the first case body T1 and the second case body T2 are integrated. Based on the rising height H1 along the tire radial direction RD and the rising angle θ from the inner end P2 of the bead portion 1 to the outer end P1 of the belt 6, from the outer end P1 of the belt 6 to the inner end P2 of the bead portion 1 A first distance L1 in the tire axial direction AD is calculated from both ends (P1, P1) of the belt 6 in the tire axial direction AD to the outside in the tire axial direction AD. The second distance L2 may be calculated by adding it to the directional dimension L0.

Although the embodiments of the present disclosure have been described above with reference to the drawings, the specific configuration should not be considered to be limited to these embodiments. The scope of the present disclosure is indicated not only by the description of the above embodiments but also by the claims, and further includes all modifications within the meaning and scope equivalent to the claims.

The structures employed in each of the above embodiments can be employed in any other embodiment. The specific configurations of each part are not limited to the above-mentioned embodiments, and various modifications are possible without departing from the spirit of this disclosure.

For example, the execution order of each process such as operation, procedure, step, and stage in the apparatus, system, program, and method shown in the claims, specification, and drawings is such that the output of the previous process is They can be implemented in any order unless used in processing. Even if "first", "next", etc. are used to explain the claims, specification, and flows in the drawings for convenience, this does not mean that they must be executed in this order. .

1: Bead portion 3: Tread 4: Carcass 5: Inner liner 6: Belt 8: Tread rubber 50: Carcass band drum 53: Belt drum 510: Chuck AD: Tire axial direction H1: Rising height L0: Tire axial dimension L1 : First distance L2 : Second distance P1 : Outer end of belt 6 P2 : Inner end of bead part 1 RD : Tire radial direction T1 : First case body T2 : Second case body θ : Rising angle

Claims (5)

Winding a plurality of tire components including an inner liner and a carcass around a carcass band drum to generate a cylindrical first case body having a pair of bead portions;
Winding a plurality of tire components including a tread rubber and a belt around a belt drum to generate a cylindrical second case body;
calculating a first distance in the tire axial direction from the outer end of the belt to the inner end of the bead portion based on a rise height in the tire radial direction from the inner end of the bead portion to the outer end of the belt when the first case body and the second case body are integrated and a rise angle from the inner end of the bead portion toward the outer end of the belt;
Calculating second distances by adding the first distances to the axial dimension of the belt from both ends of the belt toward the axially outward direction of the belt;
In a state in which the pair of bead portions of the first case body are held by a pair of chucks, respectively, the first case body is inflated while reducing a separation distance between the bead portions held by the pair of chucks in the tire axial direction to a second distance, thereby integrating the first case body and the second case body.
A method for manufacturing a pneumatic tire, comprising: The pneumatic pump according to claim 1, wherein the rising height is calculated based on a diameter difference between the carcass band drum and the belt drum, and the rising angle is calculated based on the cross-sectional height of the tire after tire vulcanization. How tires are manufactured. The rising angle corresponding to the designated tire cross-sectional height is specified based on a plurality of data relating the rising angle and the tire cross-sectional height, and the first distance is calculated using the specified rising angle. , The method for manufacturing a pneumatic tire according to claim 2. When the tire cross-sectional height is less than 100 mm, the rising angle is 85 degrees, and when the tire cross-sectional height is 100 mm or more and less than 120 mm, the rising angle is 80 degrees. 4. The method for manufacturing a pneumatic tire according to claim 3, wherein the rising angle is 75 degrees when the tire cross-sectional height is 120 mm or more and 140 mm or less. a carcass band drum around which a plurality of tire members including an inner liner and a carcass are wound to produce a cylindrical first case body having a pair of bead portions;
a belt drum around which a plurality of tire members including tread rubber and a belt are wound to produce a cylindrical second case body;
While the pair of bead portions of the first case body are each held by a pair of chucks, while inflating the first case body, the separation distance of the pair of chucks along the tire axial direction is reduced to a second distance. , configured to integrate the first case body and the second case body,
The rising height along the tire radial direction from the inner end of the bead part to the outer end of the belt when the first case body and the second case body are integrated, and the belt from the inner end of the bead part A first distance in the tire axial direction from the outer end of the belt to the inner end of the bead portion is calculated based on the rising angle toward the outer end of the belt.
A pneumatic tire manufacturing apparatus, wherein the second distance is calculated by adding the first distance to the axial dimension of the belt from both ends of the belt in the tire axial direction toward the outside in the tire axial direction. .