KR101592585B1 - Mold for tire - Google Patents

Abstract

SUMMARY OF THE INVENTION It is an object of the present invention to provide a tire having a tread pattern of a pitch variation type and excellent in uniformity.
The tread ring (16) of the tire mold has a concavo-convex shape on its inner circumferential surface. This uneven shape is made up of a number of elements. These elements include a first element LL, a second element L, a third element M, a fourth element S and a fifth element SS. The first element LL and the second element L have a pitch larger than the average pitch Pa. The third element M has a pitch substantially equal to the average pitch Pa. The fourth element S and the fifth element SS have a pitch smaller than the average pitch Pa. The tread ring 16 is divided into nine segments by the dividing surfaces 22a-22i. Elements LL, L and M having pitches equal to or more than the average pitch exist at the positions of the respective divisional surfaces.

Description

Tire mold {MOLD FOR TIRE}

The present invention relates to a mold used in a vulcanizing process of a tire.

BACKGROUND ART [0002] In a vulcanizing process of a tire, a split mold is used. The split mold is provided with a tread ring. The inner circumferential surface of the tread ring is provided with a concavo-convex shape. The tire obtained from the split mold has a tread having a shape in which the shape of the unevenness is reversed. A tread pattern is formed by the irregular shape. The tread ring is divided into a plurality of segments by a plurality of divided surfaces. These segments are arranged along the circumferential direction. Such a split mold is disclosed in Japanese Patent Application Laid-Open No. 11-198145.

The tread pattern may be divided into a plurality of elements arranged in the circumferential direction. A tread pattern composed of a plurality of kinds of elements having different pitches in the circumferential direction is employed. This pattern is referred to as a " pitch variation type ". In a tire having this pattern, noise caused by the pattern can be suppressed. A variable pitch type tread pattern is disclosed in Japanese Patent Application Laid-Open No. 2005-246931.

Japanese Patent Application Laid-Open No. 11-198145 Japanese Patent Application Laid-Open No. 2005-246931

An end face of the segment is located on the division face of the split mold. When the mold is closed, the end face of the segment is in contact with the end face of the adjacent segment. On the end face, compressive force is applied. When the mold is opened, the end faces are spaced apart from each other. As the mold is repeatedly opened and closed, a plastic deformation occurs in the vicinity of the end face of the inner peripheral face of the segment. The vicinity of the end face protrudes toward the inside in the radial direction. This protrusion impairs the uniformity of the tire.

In the variable pitch type tread pattern, the strength of the segment tends to be insufficient in the element having a small pitch. There is a case where the segment protrudes radially inward at a position where an element having a small pitch exists due to the contact between the segments when the mold is opened and closed.

A variable pitch type tread pattern may be formed by a split mold. The uniformity of the tire obtained from the split mold in which the element having a small pitch is located on the divided surface is largely inferior. The reason for this is that unevenness caused by elements with small pitches promotes nonuniformity due to the divisional surface.

It is an object of the present invention to provide a tire having a variable pitch type tread pattern and excellent uniformity.

The mold for a tire according to the present invention has a tread ring having an inner peripheral surface on the inner peripheral surface of the tread pattern of the tire. The tread ring is divided into a plurality of segments arranged along the circumferential direction by a plurality of dividing surfaces. The concavo-convex shape is composed of a plurality of kinds of elements having different pitches in the circumferential direction. At each of the divisional surfaces, there is an element having a pitch equal to or larger than the average pitch. Preferably, there is an element having a pitch of 1.03 times or more of the average pitch at the position of each division face. Preferably, there is no element having a pitch less than the average pitch in the vicinity of each division surface.

According to another aspect of the present invention, a mold for a tire has a tread ring having an uneven surface for a tread pattern of the tire on an inner peripheral surface thereof. The tread ring is divided into a plurality of segments arranged along the circumferential direction by a plurality of dividing surfaces. The concavo-convex shape is composed of a plurality of kinds of elements having different pitches in the circumferential direction. When these plural kinds of elements are arranged in order of pitch, there exists a kind of element that can be included in the upper 50% at the position of each division face. Preferably, there is no element that can not be included in the upper 50% in the vicinity of each division plane.

Wherein the concavo-convex shape includes a first element, a second element having a pitch smaller than the pitch of the first element, a third element having a pitch smaller than the pitch of the second element, A fourth element, and a fifth element having a pitch smaller than the pitch of the fourth element. Preferably, a first element, a second element, or a third element is present at the position of each divisional surface. Preferably, the first element or the second element is present at the position of each divisional surface.

A tire according to the present invention is molded by a mold having a tread ring divided into a plurality of segments arranged along the circumferential direction by a plurality of dividing surfaces. The tire has a tread pattern composed of a plurality of kinds of elements having different pitches in the circumferential direction. At each position corresponding to the dividing surface, there is an element having a pitch equal to or larger than the average pitch.

According to another aspect of the present invention, a tire is formed by a mold having a tread ring divided into a plurality of segments arranged along the circumferential direction by a plurality of dividing surfaces. The tire has a tread pattern composed of a plurality of kinds of elements having different pitches in the circumferential direction. There are elements of a kind that can be included in the upper 50% when these plural kinds of elements are arranged in order of pitch in each position corresponding to the division plane.

A method of manufacturing a tire according to the present invention comprises:

(1) a step of obtaining a low cover by preliminary molding,

(2) a tread ring having, on its inner circumferential surface, an irregular shape for a tread pattern of a tire,

The tread ring is divided into a plurality of segments arranged along the circumferential direction by a plurality of dividing surfaces,

The concavo-convex shape is composed of a plurality of kinds of elements having different pitches in the circumferential direction,

A step of putting the row cover into a mold in which an element having a pitch equal to or more than the average pitch exists at each of the divided surfaces,

(3) pressing and heating the row cover in the mold

.

According to another aspect of the present invention,

(1) a step of obtaining a low cover by preliminary molding,

(2) a tread ring having, on its inner circumferential surface, an irregular shape for a tread pattern of a tire,

The tread ring is divided into a plurality of segments arranged along the circumferential direction by a plurality of dividing surfaces,

The concavo-convex shape is composed of a plurality of kinds of elements having different pitches in the circumferential direction,

A step of inserting the row cover into a mold in which elements of a kind that can be included in the upper 50% are present at the positions of the respective divided surfaces when the plural kinds of elements are arranged in the order of pitch; and

(3) pressing and heating the row cover in the mold

.

In the mold according to the present invention, there is no dividing surface at the position of the element having a small pitch. In the tire obtained by this mold, the unevenness caused by the element having a small pitch does not promote the unevenness due to the divided surface. This tire is excellent in uniformity.

1 is a developed view showing a part of a tire according to an embodiment of the present invention.
Figure 2 is a developed view of the elements of the tread pattern of the tire of Figure 1;
3 is a plan view showing a mold for the tire of Fig.
4 is an enlarged cross-sectional view taken along the line IV-IV in Fig.
5 is a schematic diagram showing the arrangement of the elements of the tread ring of the mold shown in Fig.
6 is a schematic diagram showing a tread ring of a tire mold according to another embodiment of the present invention.
7 is a schematic diagram showing a tread ring of a tire mold according to a comparative example.

Best Mode for Carrying Out the Invention Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the drawings as appropriate.

1 is a developed view showing a part of a tire 2 according to an embodiment of the present invention. In Figure 1, a tread surface 4 is shown. The tread surface (4) has a plurality of grooves (6). A portion of the tread surface 4 other than the groove 6 is a land 8. The groove 6 and the land 8 form a tread pattern.

2 is a developed view showing the elements of the tread pattern of the tire 2 of Fig. This tread pattern consists of a first element LL, a second element L, a third element M, a fourth element S and a fifth element SS. 2, the arrow P1 indicates the pitch in the circumferential direction of the first element LL, the arrow P2 indicates the pitch in the circumferential direction of the second element L, and the arrow P3 indicates the pitch in the circumferential direction of the third element M The arrow P4 indicates the pitch in the circumferential direction of the fourth element S and the arrow P5 indicates the pitch in the circumferential direction of the fifth element SS. The pitch P2 is smaller than the pitch P1. The pitch P3 is smaller than the pitch P2. The pitch P4 is smaller than the pitch P3. The pitch P5 is smaller than the pitch P4. This tread pattern is a variable pitch type. The number of kinds of elements is five.

The mold for molding the tire 2 has, on its inner circumferential surface, a concavo-convex shape composed of a striped mountain and a land. This uneven shape has a pattern of a shape in which the shape of the tread pattern is inverted. The stripe of the mold corresponds to the groove 6 of the tread. The land of the mold corresponds to the land 8 of the tread. The uneven shape of the mold is also made up of a first element LL, a second element L, a third element M, a fourth element S and a fifth element SS.

3 is a plan view showing the mold 10 for the tire 2 of Fig. 4 is an enlarged cross-sectional view taken along the line IV-IV in Fig. In Fig. 3, a mold 10 in a closed state is shown. The mold 10 includes a pair of upper and lower side plates 12, a pair of upper and lower bead rings 14, and a tread ring 16. The side plate 12 and the bead ring 14 are substantially ring-shaped.

The tread ring 16 comprises a plurality of segments 18. These segments 18 are arranged in the circumferential direction. This mold 10 is a so-called " split mold ". The tread ring 16 is divided at the dividing surface, so that the segment 18 is obtained. The planar shape of each segment 18 is substantially circular arc. The dividing surface extends in the radial direction. The end face 20 of one segment 18 is in contact with the end face 20 of the other segment 18. The segment 18 is provided with an uneven shape (not shown) made up of striped mountains and lands on its inner peripheral surface. The number of the segments 18 is three or more and twenty or less. In the embodiment of Fig. 3, the number of segments 18 is nine.

What is indicated by an arrow? In FIG. 3 is the central angle of the segment 18. 3, the central angle [theta] of one segment 18 is different from the central angle [theta] of the other segment 18. The tread ring 16 is unevenly divided.

Fig. 5 is a schematic diagram showing the arrangement of the elements of the tread ring 16 of the mold 10 shown in Fig. In Fig. 5, the symbol LL is the first element, the symbol L is the second element, the symbol M is the third element, and the symbol S is the fourth element , And the one indicated by the symbol SS is the fifth element. The tread ring 16 has nine first elements LL, fifteen second elements L, seventeen third elements M, thirteen fourth elements S, ten And a fifth element (SS). The total number of elements is 64.

In this embodiment, when the pitch P3 of the third element M is 1.00 (exponent), the pitch P1 of the first element LL is 1.15 and the pitch P2 of the second element L is 1.15 The pitch P4 of the fourth element S is 0.93 and the pitch P5 of the fifth element SS is 0.84. The average pitch Pa is calculated by the following equation.

Pa = (1.15 * 9 + 1.08 * 15 + 1.00 * 17 + 0.93 * 13 + 0.84 * 10) / 64

The average pitch Pa of the tread rings 16 is 1.00. The first element LL and the second element L have a pitch larger than the average pitch Pa. The third element M has a pitch substantially equal to the average pitch Pa. The fourth element S and the fifth element SS have a pitch smaller than the average pitch Pa.

In this embodiment, the number of kinds of elements is five. When these five types of elements are arranged in order of pitch, the types that can be included in the top 50% are the first, second, and third kinds. In this embodiment, the first element LL, the second element L and the third element M are elements of a kind that can be included in the upper 50%.

In Fig. 5, divisional surfaces 22a-22i are indicated by two-dot chain lines. As described above, since the tread ring 16 has nine segments 18, the number of the dividing surfaces 22 is nine. On this dividing surface 22, the end face 20 (see Fig. 3) of the segment 18 is located.

At the position of the divisional surface 22a, the third element M exists. At the position of the divisional surface 22b, the second element L exists. At the position of the divisional surface 22c, the third element M exists. At the position of the divisional surface 22d, the second element L exists. At the position of the divisional surface 22e, the first element LL exists. At the position of the divisional surface 22f, the second element L exists. At the position of the divisional surface 22g, the second element L exists. At the position of the divisional surface 22h, the third element M exists. At the position of the divisional surface 22i, the third element M exists. These divided surfaces 22 can be classified into the following groups.

The divisional surface in which the first element LL exists at that position: 1

The division surface on which the second element L exists is 4

The divisional surface in which the third element M exists at that position: 4

The fourth element S does not exist at the position of the divisional surface 22. The fifth element SS does not exist at the position of the dividing surface 22 as well.

In the mold 10, the elements LL, L and M having a pitch equal to or more than the average pitch are present at the positions of the respective divisional surfaces 22. Two elements may be adjacent to each other with the divisional surface 22 therebetween. In this case, in the present invention, a state in which both elements have a pitch equal to or more than the average pitch is a state in which " an element having a pitch equal to or more than the average pitch exists at the position of the dividing face ".

In this mold 10, when the kinds of the elements LL, L, M, S, and SS are arranged in the order of pitches larger, The elements LL, L, and M of FIG. Two elements may be adjacent to each other with the divisional surface 22 therebetween. In this case, in the present invention, a state in which both elements are included in the upper 50% is a state in which a kind of element that can be included in the upper 50% exists in the position of the divisional surface.

In the method of manufacturing the tire 2 using the mold 10, a low cover (unvulcanized tire) is obtained by preliminary molding. This row cover is put into the mold 10 in a state in which the mold 10 is opened and the bladder is contracted. The mold 10 is closed, and the bladder is inflated. The low cover is pressed against the cavity surface of the mold 10 by a bladder and pressed. The low cover 24 in this state is shown in Fig. At the same time, the row cover is heated. The rubber composition flows by pressurization and heating. The rubber causes a crosslinking reaction by heating to obtain a tire 2. A tread pattern is formed on the tire 2 by the uneven shape (not shown) existing on the cavity surface 26 of the segment 18. [ The process in which the low cover is pressed and heated is referred to as a vulcanization process. Instead of a bladder, a core may be used.

In the tire 2 obtained by the mold 10, the first element LL, the second element L, or the third element M exists at a position corresponding to the dividing surface 22 . The fourth element S and the fifth element SS do not exist at the positions corresponding to the dividing surface 22. In this tire 2, elements LL, L and M having a pitch equal to or more than the average pitch exist at respective positions corresponding to the dividing surface 22. In this tire 2, when the types of the elements LL, L, M, S, and SS are arranged at the positions corresponding to the dividing surface 22 in the order of pitch, There are elements LL, L and M, which are types.

Plastic deformation occurs in the vicinity of the end face 20 of the inner peripheral surface of the segment 18 by repeating the opening and closing of the mold 10. [ The vicinity of the end surface (20) protrudes radially inward. This projection deteriorates the uniformity of the tire 2. In the variable pitch type tread pattern, the segment may protrude radially inward at a position where an element with a small pitch exists. This protrusion also impairs the uniformity of the tire 2. In the tire 2 according to the present invention, the elements S and SS having small pitches do not exist at positions corresponding to the dividing surface 22. Therefore, unevenness caused by the elements S and SS having a small pitch does not promote nonuniformity due to the dividing face 22. The tire (2) is excellent in uniformity.

It is preferable that elements S and SS having a pitch smaller than the average pitch Pa are not present in the vicinity of the dividing surface 22 of the mold 10 from the viewpoint of uniformity. From the viewpoint of uniformity, it is preferable that no elements S and SS of the kind that can not be included in the upper 50% are present in the vicinity of the dividing surface 22 of the mold 10. [ Means a region having a center angle of -2 DEG or more and + 2 DEG or less centering on the dividing surface 22. The term " near the dividing surface 22 " Preferably, the " neighborhood of the dividing surface 22 " is a region having a central angle of -3 DEG or more and + 3 DEG or less centering on the dividing surface 22. [ More preferably, the " neighborhood of the dividing surface 22 " is a region having a central angle of -5 DEG or more and +5 DEG or less centering on the dividing surface 22. [

6 is a schematic diagram showing a tread ring 30 of a mold for a tire according to another embodiment of the present invention. 6, the arrangement of the elements of the tread ring 30 is shown. In Fig. 6, the symbol LL is the first element, the symbol L is the second element, the symbol M is the third element, and the symbol S is the fourth element , And the one indicated by the symbol SS is the fifth element. The tread ring 30 has nine first elements LL, fifteen second elements L, seventeen third elements M, thirteen fourth elements S, ten And a fifth element (SS). The total number of elements is 64.

In this embodiment, when the pitch P3 of the third element M is 1.00 (exponent), the pitch P1 of the first element LL is 1.15 and the pitch P2 of the second element L is 1.15 The pitch P4 of the fourth element S is 0.93 and the pitch P5 of the fifth element SS is 0.84. The average pitch (Pa) of the mold is 1.00. The number of kinds of elements of this mold is five. When these five types of elements are arranged in the order of pitch, the types of elements that can be included in the upper 50% are the first element LL, the second element L and the third element M. [

In Fig. 6, divisional surfaces 32a-32i are indicated by two-dot chain lines. The number of segments of this mold is nine, and the number of the divisional surfaces 32 is nine. The second element L exists at the position of the divisional surface 32a. At the position of the divisional surface 32b, the second element L exists. At the position of the divisional surface 32c, the second element L exists. At the position of the divisional surface 32d, the second element L exists. The first element LL exists at the position of the divisional surface 32e. At the position of the divisional surface 32f, the second element L exists. At the position of the divisional surface 32g, the second element L exists. At the position of the divisional surface 32h, the second element L exists. The first element LL exists at the position of the divisional surface 32i. These divided surfaces 32 can be classified into the following groups.

The divisional surface in which the first element LL exists at that position: 2

And the divisional surface 7 in which the second element L is present is 7

The third element M does not exist at the position of the dividing surface 32. [ The fourth element S does not exist at the position of the divisional surface 32. [ The fifth element SS is also not present at the position of the dividing surface 32. [

In this mold, elements LL and L having a pitch larger than the average pitch exist at the positions of the respective divisional surfaces 32. [ In this mold, there are no elements S and SS having a pitch smaller than the average pitch at the position of the dividing surface 32. [ Also, at the position of the dividing surface 32, there is no element M having a pitch substantially equal to the average pitch. The tire obtained by this mold has excellent uniformity.

From the viewpoint of uniformity, it is preferable that an element having a pitch of 1.03 times or more the average pitch exists at the position of each of the dividing planes 32. [ It is particularly preferable that an element having a pitch of 1.06 times or more of the average pitch exists at the position of each of the dividing planes 32. [

The uneven shape of the mold may be composed of the first element and the second element. The number of kinds of elements of this irregular shape is two. The pitch of the second element is smaller than the pitch of the first element. In this mold, when these two types of elements are arranged in order of pitch, the kind of element that can be included in the top 50% is the first element. At the position of each divisional surface, there is a first element. In the tread pattern of the tire obtained from the mold, the first element exists at each position corresponding to the dividing surface.

The uneven shape of the mold may be composed of the first element, the second element and the third element. The number of elements of this concavo-convex shape is three. The pitch of the second element is smaller than the pitch of the first element. The pitch of the third element is smaller than the pitch of the second element. In this mold, when these three kinds of elements are arranged in order of pitch, the kinds of elements that can be included in the upper 50% are the first element and the second element. At the position of each divisional surface, there is a first element or a second element. Preferably, the first element is present at the position of each divisional surface. In the tread pattern of the tire obtained from the mold, the first element or the second element is present at each position corresponding to the dividing surface. Preferably, the first element is present at each position corresponding to the dividing plane.

The uneven shape of the mold may be composed of the first element, the second element, the third element and the fourth element. The number of elements of this concavo-convex shape is four. The pitch of the second element is smaller than the pitch of the first element. The pitch of the third element is smaller than the pitch of the second element. The pitch of the fourth element is smaller than the pitch of the third element. In this mold, when these four kinds of elements are arranged in the order of pitch, the kinds of elements that can be included in the upper 50% are the first element and the second element. At the position of each divisional surface, there is a first element or a second element. In the tread pattern of the tire obtained from the mold, the first element or the second element is present at each position corresponding to the dividing surface.

The uneven shape of the mold may be composed of the first element, the second element, the third element, the fourth element, the fifth element and the sixth element. The number of elements of this irregular shape is six. The pitch of the second element is smaller than the pitch of the first element. The pitch of the third element is smaller than the pitch of the second element. The pitch of the fourth element is smaller than the pitch of the third element. The pitch of the fifth element is smaller than the pitch of the fourth element. The pitch of the sixth element is smaller than the pitch of the fifth element. In this mold, when these six kinds of elements are arranged in the order of pitch, the kinds of elements that can be included in the upper 50% are the first element, the second element and the third element. At the position of each divisional surface, there is a first element, a second element, or a third element. In the tread pattern of the tire obtained from the mold, the first element, the second element, or the third element exists at each position corresponding to the dividing surface.

(N / 2 + 1) -th to n-th elements are present at the positions of the respective divisional surfaces when the number of kinds of the irregular-shaped elements is n (n is an even number of 2 or more). In the tread pattern of the tire obtained from this mold, one of the (n / 2 + 1) th to nth elements is present at each position corresponding to the dividing surface.

(N-1) / 2 + 1) -th element to the n-th element exists at the positions of the respective divisional surfaces when the number of kinds of the irregular-shaped elements is n (n is an odd number of 3 or more). Preferably, one of the ((n-1) / 2 + 2) -th to n-th elements is present at the position of each of the divisional surfaces. In the tread pattern of the tire obtained from this mold, any one of the ((n-1) / 2 + 1) th element to the n-th element exists at each position corresponding to the dividing surface. Preferably, any one of the ((n-1) / 2 + 2) th element to the n-th element exists at each position corresponding to the divisional surface.

(Example)

Hereinafter, the effects of the present invention will be apparent from the examples, but the present invention should not be construed on the basis of the description of these examples.

[Example 1]

The molds shown in Figs. 3 to 5 were prepared. The mold was attached to a vulcanizer, and the mold was opened and closed 3,000 times. This mold was used to produce 50 tires each having a size of " 235 / 55R18 ". The tread pattern of this tire is shown in Figs. 1 and 2. Fig. After opening and closing 3,000 times (6000 times in total), 50 tires were manufactured. After opening and closing 4000 times (10000 times in total), 50 tires were manufactured.

[Example 2]

A tire was obtained in the same manner as in Example 1 except that a mold having a dividing surface shown in Fig. 6 was used.

[Comparative Example]

A tire was obtained in the same manner as in Example 1 except that a mold having a dividing surface shown in Fig. 7 was used. The tread ring 34 of this mold has nine divided surfaces 36. [

[Evaluation of uniformity]

The RFV was evaluated in accordance with JASO C607: 2000 " Test method for uniformity of automobile tires ". The test conditions are as follows.

Rim: 18 × 7.5-J

Tire rotation speed: 60 rpm

Air pressure: 200 ㎪

Load weight: 6.67 kN

The average value of the measurement results of 50 tires is shown in Table 1 as an index. The smaller the number, the better.

Evaluation results Example 1 Example 2 Comparative Example The pattern of the divided surface 5 6 7 Number of division faces  The first element LL One 2 -  The second element L 4 7 5  The third element M 4 - 2  The fourth element S - - 2 RFV After opening and closing 3000 times 100 100 100 After 6000 times of opening and closing 100 100 101 After opening and closing 10,000 times 102 101 105

As shown in Table 1, the tires obtained by the molds of the examples are excellent in uniformity. From this evaluation result, the superiority of the present invention is evident.

The mold according to the present invention is suitable for manufacturing various tires.

2: Tire
4: Tread face
6: Home
8: Land
10: Mold
12: Side plate
14: Bead ring
16, 30: Tread ring
18: Segment
20: end face
22a-22i:
24: Low cover
26: Cavity face
32a-32i:

Claims (11)

And a tread ring having an inner peripheral surface of a tread pattern for a tread pattern of the tire,
The tread ring is divided into a plurality of segments arranged along the circumferential direction by a plurality of dividing surfaces,
The concavo-convex shape is composed of a plurality of kinds of elements having different pitches in the circumferential direction,
There is an element having a pitch equal to or larger than the average pitch at the positions of the respective divisional surfaces,
Wherein no element having a pitch less than the average pitch is present in a region whose central angle is less than or equal to a predetermined angle with respect to each of the divided surfaces. The tire according to claim 1, wherein an element having a pitch of 1.03 times or more of the average pitch exists at a position of each of the divisional surfaces. delete And a tread ring having an inner peripheral surface of a tread pattern for a tread pattern of the tire,
The tread ring is divided into a plurality of segments arranged along the circumferential direction by a plurality of dividing surfaces,
The concavo-convex shape is composed of a plurality of kinds of elements having different pitches in the circumferential direction,
When the plurality of types of elements are arranged in the order of pitch, there exist elements of a kind that can be included in the upper 50% at the positions of the respective divisional surfaces,
Wherein no element that can not be included in the upper 50% exists in a region where the central angle is less than or equal to a certain angle around each divided surface. delete 5. The device according to claim 4, wherein the concavo-convex shape includes a first element, a second element having a pitch smaller than the pitch of the first element, a third element having a pitch smaller than the pitch of the second element, A fourth element having a pitch smaller than the pitch, and a fifth element having a pitch smaller than the pitch of the fourth element,
Wherein a first element, a second element or a third element is present at a position of each of the divided surfaces. The tire according to claim 6, wherein a first element or a second element is present at each of the divisional surfaces. A mold having a tread ring divided into a plurality of segments arranged along the circumferential direction by a plurality of dividing surfaces,
And a tread pattern composed of a plurality of kinds of elements having different pitches in the circumferential direction,
There is an element having a pitch equal to or more than the average pitch at each position corresponding to the division plane,
Wherein no element having a pitch less than the average pitch exists in the region where the central angle is less than or equal to a certain angle with respect to each of the divided surfaces. A mold having a tread ring divided into a plurality of segments arranged along the circumferential direction by a plurality of dividing surfaces,
And a tread pattern composed of a plurality of kinds of elements having different pitches in the circumferential direction,
When the plural kinds of elements are arranged in the order of pitch, there exist elements of a kind that can be included in the upper 50% at each position corresponding to the division plane,
A tire whose center angle is less than a certain angle with respect to each of the divided planes has no element that can not be included in the upper 50%. (1) a step of obtaining a low cover by preliminary molding,
(2) a tread ring having, on its inner circumferential surface, an irregular shape for a tread pattern of a tire,
The tread ring is divided into a plurality of segments arranged along the circumferential direction by a plurality of dividing surfaces,
The concavo-convex shape is composed of a plurality of kinds of elements having different pitches in the circumferential direction,
A step of putting the row cover into a mold in which an element having a pitch equal to or more than the average pitch exists at each of the divided surfaces,
(3) pressing and heating the row cover in the mold
/ RTI >
Wherein the mold has no element having a pitch less than the average pitch in a region whose center angle is less than or equal to a certain angle with respect to each of the divided surfaces. (1) a step of obtaining a low cover by preliminary molding,
(2) a tread ring having, on its inner circumferential surface, an irregular shape for a tread pattern of a tire,
The tread ring is divided into a plurality of segments arranged along the circumferential direction by a plurality of dividing surfaces,
The concavo-convex shape is composed of a plurality of kinds of elements having different pitches in the circumferential direction,
A step of inserting the row cover into a mold in which elements of a kind that can be included in the upper 50% are present at the positions of the respective divided surfaces when the plural kinds of elements are arranged in the order of pitch; and
(3) pressing and heating the row cover in the mold
/ RTI >
Wherein the mold has no elements that can not be included in the upper 50% in a region where the central angle is less than a predetermined angle with respect to each of the divided surfaces.

Images