JP5523256B2 - Tire mold - Google Patents

Description

  The present invention relates to a tire mold for vulcanizing a tire, and more specifically, a plurality of pieces in which sectors contacting with a tread surface of a tire are arranged in a circumferential direction, and the plurality of pieces are mounted on an inner surface side. The present invention relates to a tire mold including a case to be manufactured.

  This type of tire mold is also called a piece mold, and is disclosed, for example, in Patent Documents 1 and 2 below. In the piece mold, there is an advantage that air between the tread surface of the tire and the molding surface of the mold can be discharged through a gap formed between adjacent pieces. However, it is necessary to accurately adjust the gap between the pieces. If this gap is too large, rubber flows in and burr is formed on the tread surface. Conversely, if the gap is too small, the remaining air causes A dent is formed.

  As illustrated in FIG. 8, the piece 16 is mounted on the inner surface side of the case 17, and the plurality of pieces 16 are arranged in the circumferential direction CD when in use. In a non-heated state before vulcanization molding, a clearance is provided between the piece 16 and the case 17, and the piece 16 is slidably fitted in the circumferential direction CD. Moderately dispersed. This clearance decreases when the mold is heated to shift to the heating state during vulcanization molding, and the piece 16 is fixed to the case 17 by an interference fit. At this stage, the gap between the pieces is determined, and the size of the gap does not change even if the mold opening / closing operation is repeated.

  By the way, the posture of the piece 16 attached to the case 17 is easily inclined in the α or β direction due to the above-mentioned clearance, and the inclined piece 16 is caught on the case 17 or an adjacent piece, thereby causing a phenomenon called galling. It may happen. When galling occurs, the sliding of the pieces 16 is hindered, so that the gaps between the pieces become non-uniform, causing burrs and the like on the tread surface of the vulcanized tire. As described above, in the piece mold, it is important to prevent the galling by suppressing the inclination of the piece while ensuring the sliding of the piece.

  Patent Document 1 below describes a piece mold in which a pin-shaped convex portion provided on the back surface of a piece is fitted to a concave portion provided on the inner surface of the case. However, this mold is intended to allow the pieces to be arranged in order at predetermined positions when the pieces are mounted on the case, and does not disclose a structure that can prevent the galling by suppressing the inclination of the pieces. . In particular, this pin-like convex portion is in line contact with the side wall of the concave portion, so that it is considered that the effect of suppressing the inclination of the piece is poor.

  Patent Document 2 below describes a piece mold in which a piece attached to the center of a sector is fixed to a case with a bolt from the back. However, in this mold, even if the central piece is fixed in an appropriate posture, the pieces arranged on both sides of the mold have no measures to suppress the inclination, and may still cause galling. Concerned.

JP-A-7-314459 JP 2006-159669 A

  This invention is made | formed in view of the said situation, The objective is to provide the tire mold which suppresses the inclination of the piece and prevents a galling, ensuring the sliding of a piece.

  The above object can be achieved by the present invention as described below. That is, in the tire mold according to the present invention, a sector that contacts the tread surface of a tire set with the width direction set up and down has a plurality of pieces arranged in the circumferential direction, and the plurality of pieces are mounted on the inner surface side. In the tire mold provided with a case, a rail extending in the circumferential direction protrudes from the inner surface of the case, and a fitting groove that fits the rail is recessed in the back of each piece, The lower surface of the joint groove is formed so as to be in surface contact with the lower surface of the rail, and when the lower end surface of the piece mounted on the case is brought into contact with the inner surface of the lower end portion of the case, vulcanization is performed. In a non-heated state before molding, a clearance C1 between the lower surface of the fitting groove and the lower surface of the rail, and a clearance C2 between the upper end surface of the piece and the inner surface of the upper end portion of the case Provided Is intended C1 is smaller than C2.

  In this tire mold, the rail provided on the inner surface of the case is fitted in the fitting groove on the back of each piece, and clearances C1 and C2 are provided in a non-heated state before vulcanization molding. The tilt of the piece can be suppressed while securing In addition, since C1 is smaller than C2, when the temperature of the mold is raised and the state is changed to the heating state at the time of vulcanization, the clearance C1 disappears first, and then the clearance C2 disappears. As a result, the lower part extending from the lower end surface of the piece to the lower surface of the fitting groove is tightly fitted before the entire part of the piece. Can be prevented.

  In the present invention, it is preferable that the fitting groove and the rail are fitted at one place in the width direction, and the lower side surface of the fitting groove is positioned above the center in the width direction of the piece. By fitting the fitting groove and the rail at one place in the width direction, the sliding resistance can be made as small as possible and the sliding of the pieces can be easily ensured. In addition, by placing the lower side of the fitting groove above the center in the width direction of the piece, the width of the lower part of the piece to be fitted first is secured, so that the lower part of the piece is tightly fitted. The inclination of the upper part of the piece can be effectively suppressed at the stage.

  Further, another tire mold according to the present invention includes a plurality of pieces in which sectors contacting with a tread surface of a tire set with the width direction set up and down are arranged in the circumferential direction, and the plurality of pieces on the inner surface side. In a tire mold including a case to be mounted, a rail extending in the circumferential direction protrudes on the inner surface of the case, and a fitting groove that fits the rail is recessed on the back surface of each piece. The lower surface of the fitting groove is formed so as to be in surface contact with the lower surface of the rail, and the fitting groove and the rail are fitted at two places in the width direction. The lower side surface is positioned above the center in the width direction of the piece, and the lower side surface of the lower fitting groove is positioned below the center in the width direction of the piece, and is in a non-heated state before vulcanization molding. The upper side surface of the lower fitting groove is The clearance C3 between the lower side surface of the upper fitting groove and the lower side surface of the rail when contacting the upper side surface of the rail, and between the upper end surface of the piece and the inner surface of the upper end portion of the case Clearance C4, clearance C5 between the lower end surface of the piece and the inner surface of the lower end portion of the case, and clearance C6 between the lower side surface of the lower fitting groove and the lower side surface of the rail are provided. C3 is smaller than C4 and C5, and C6 is larger than C4 and C5.

  Also in this tire mold, the rail provided on the inner surface of the case is fitted in the fitting groove on the back of each piece, and each clearance is provided in a non-heated state before vulcanization molding, so that the piece slides. While securing, the inclination of the piece can be suppressed. Moreover, since C3 is smaller than C4 and C5, the clearance C3 disappears first, and then the clearances C4 and C5 disappear when the mold is heated to shift to the heating state during vulcanization molding. As a result, prior to the whole part of the piece, the center part extending from the upper side surface of the lower fitting groove to the lower side surface of the upper fitting groove is tightly fitted, and the parallelism between adjacent pieces can be accurately and quickly adjusted. It is possible to effectively prevent galling. The piece is strongly fitted to the case when the clearances C4 and C5 disappear. However, since the clearance C6 has not yet disappeared at this point, the parallelism of the pieces is not affected.

  In the present invention, it is preferable that the lower surface of the fitting groove and the lower surface of the rail are formed along the radial direction. According to such a configuration, when shifting from the non-heated state to the heated state, the pressing force when the lower side surface of the fitting groove comes into surface contact with the lower side surface of the rail remains in the width direction, and the piece due to the pressing force Can be effectively prevented by preventing displacement in the radial direction.

In the present invention, the piece has an integral structure that is not divided in the width direction . Such an integrally structured piece has an advantage that the number of parts can be reduced as compared with a piece having a divided structure. However, since the piece has an elongated shape in the width direction (vertical direction), the posture is easily inclined. Therefore, the present invention that can suppress the inclination of the piece by the above-described action is particularly useful.

1 is a longitudinal sectional view schematically showing an example of a tire mold according to the present invention. Top view of the tread mold Perspective view of the sector Diagram showing the end face of the sector Perspective view of the sector The figure which shows the end surface of the sector in another embodiment of this invention The figure which shows the end surface of the sector in another embodiment of this invention Perspective view of sector with conventional tire mold

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the tire mold shown in FIG. 1 (hereinafter sometimes abbreviated as “mold”), a green tire (not shown) is set with its width direction up and down. This mold includes an annular tread mold part 1 for molding a tire tread part, side mold parts 2 and 3 for molding a tire sidewall part, and a bead ring 4 for fitting the tire bead part. Prepare. Although not shown, the molding surface 1a of the mold is provided with an uneven shape corresponding to the tread pattern.

  As shown in FIG. 2, the tread mold portion 1 is composed of a plurality of sectors 5 divided in the circumferential direction, each of which abuts on the tread surface of the tire. In the mold clamping state, the sectors 5 are connected in an annular shape with their end surfaces abutting each other, and in the mold open state, the sectors 5 are displaced radially outward and separated from each other. In the present embodiment, an example is shown in which the tread part 1 is divided into seven and the circumferences of the sectors 5 are substantially equal. However, in the present invention, the number of divisions of the tread part is not particularly limited, and the circumferences of the sectors are not limited. May be different from each other.

  As shown in FIG. 1, the mold is incorporated in a vulcanizer and used for vulcanization molding of a tire. In this vulcanizer, when the cone ring 24 is raised, the segments 21 are displaced along the slide rails 25, and the sectors 5 are separated from the side mold parts 2 and 3 radially outward. Subsequently, when the container upper plate 23 is raised, the sector 5, the side mold portion 3, and the upper bead ring 4 are separated upward, and the mold shifts to a mold open state where tires can be taken in and out. The transition from the mold open state to the mold clamped state may be performed in the reverse manner.

  As shown in FIG. 3, the sector 5 includes a plurality of pieces 6 arranged in the circumferential direction CD and a case 7 on which the plurality of pieces 6 are mounted on the inner surface side. In a clamping state where a plurality of sectors 5 are connected in an annular shape, the piece 6 has an annular shape as a whole, and its inner peripheral surface constitutes the molding surface 1a of the mold. In this embodiment, each piece 6 is a monolithic structure that is not divided in the width direction WD, and is formed monolithically from its lower end to its upper end. On both sides of the width direction WD of the case 7, hook-shaped arms 70 are provided to prevent the pieces 6 from falling out inward in the radial direction.

  FIG. 4 shows an end face of the sector 5 in a non-heated state (20 ° C.) before vulcanization molding, and FIG. 5 shows a state where only one piece 6 is removed from the sector 5 of FIG. Yes. A single rail 8 extending in the circumferential direction CD protrudes from the inner surface of the case 7 and is fitted in a fitting groove 9 that is recessed in the back of each piece 6. Each of the rail 8 and the fitting groove 9 extends with a rectangular cross section in the circumferential direction CD, and the lower side surface 9a of the fitting groove 9 is formed so as to be in surface contact with the lower side surface 8a of the rail 8.

  As shown in FIG. 4, in a posture in which the width direction WD is directed upward and downward, the piece 6 is moved downward by gravity, and the lower end surface 6 a of the piece 6 attached to the case 7 contacts the inner surface 7 a of the lower end portion of the case 7. To do. At this time, in the non-heated state before vulcanization molding, the clearance C1 between the lower side surface 9a of the fitting groove 9 and the lower side surface 8a of the rail 8, the inner surface of the upper end surface 6b of the piece 6 and the upper end portion of the case 7 A clearance C <b> 2 with respect to 7 b is provided, and the piece 6 is loosely fitted in the case 7.

  Since the clearances C1 and C2 are provided in the non-heated state, the sliding of the pieces 6 in the circumferential direction CD is ensured, and the gaps between the pieces can be appropriately dispersed on the circumference. Still, by fitting the rail 8 in the fitting groove 9, the inclination of the piece 6 can be suppressed and galling can be effectively prevented. The piece 6 is made of a material having a larger thermal expansion coefficient than that of the case 7. In the heated state (for example, 170 ° C.) at the time of vulcanization molding, the clearances C 1 and C 2 disappear due to the thermal expansion of the piece 6. Is fixed to the case 7 by an interference fit.

  In this mold, C1 is smaller than C2, and in the process of shifting to the heating state at the time of vulcanization molding, the clearance C1 disappears first, and the piece 6 is located between the lower end surface 6a and the lower side surface 9a of the fitting groove 9. Then, the lower portion A of the piece 6 is fixed, and then the clearance C2 disappears, the piece 6 is tightened between the lower end surface 6a and the upper end surface 6b, and the entire portion B of the piece 6 is fixed. Thus, since the lower part A is tightly fitted prior to the entire part B of the piece 6, it is possible to effectively fix the case 7 and prevent galling effectively.

  When the thermal expansion of the piece 6 is settled after the clearance C2 disappears, the gap between the pieces is determined. At that stage, since the piece 6 is fixed to the case 7, the size of the gap does not change even when the opening and closing operation of the mold is repeated. In this mold, since the inclination of the piece 6 can be suppressed and galling can be prevented as described above, the parallelism between adjacent pieces is maintained with high accuracy, the gap between the pieces is properly formed, and the tread surface Generation | occurrence | production of a burr | flash etc. can be suppressed favorably.

  In the present embodiment, the piece 6 is made of an aluminum material, and the case 7 is made of a steel material. Therefore, in this mold, the rail 8 is harder than the fitting groove 9, and the piece 6 can be firmly guided by the fitting. If this concavo-convex relationship is reversed, there is a concern about deformation and wear of the relatively soft rail, which may affect the effect of suppressing the inclination of the piece. The clearance C2 is set to be equal to or less than the difference in thermal expansion between the piece 6 and the case 7, and the arm 70 is configured to hold the piece 6 in a heated state.

  The height H from the inner surface of the case 7 to the top surface of the rail 8 is preferably 3 mm or more in order to ensure the action of suppressing the inclination of the piece 6. Further, from the viewpoint of securing the strength of the piece 6 itself, the height H is preferably ½ or less of the thickness T of the piece 6. The thickness T of the piece 6 is, for example, about 20 to 25 mm. The width W of the rail 8 is preferably 2 to 20 mm. If the width W is less than 2 mm, the rail 8 becomes narrower. If the width W exceeds 20 mm, the rail 8 becomes wider and workability when the piece 6 is mounted is deteriorated.

  In the present embodiment, an example is shown in which the fitting groove 9 and the rail 8 are fitted at one place in the width direction WD. In this case, as shown in FIG. 4, it is preferable that the lower surface 9 a of the fitting groove 9 is positioned above the center 6 c in the width direction of the piece 6. Thereby, the space | interval between the lower end surface 6a and the lower side surface 9a is not excessively narrowed, and the width of the lower side portion A to be tightly fitted first is ensured. As a result, when the lower portion A is tightened, the inclination of the upper portion of the piece 6 that is not yet fixed can be effectively suppressed. The center 6 c in the width direction is the center between the lower end surface 6 a and the upper end surface 6 b of the piece 6.

  The lower side surface 9a of the fitting groove 9 is preferably located within a range of 1/2 to 2/3 of the piece width PW (the length of the entire portion B in the width direction WD) from the lower end surface 6a of the piece 6. The purpose of setting the position of the lower surface 9a to ½ or more of the piece width PW is as described above. Further, by setting the position of the lower side surface 9a to 2/3 or less of the piece width PW, the lower part of the piece 6 can be fixed early in the process of raising the temperature of the mold. That is, when this exceeds 2/3 of the piece width PW, the fixing of the lower portion of the piece 6 is delayed, and the effect of preventing galling tends to be reduced.

  When the lower side surface 9a of the fitting groove 9 is located within the range of 1/2 to 2/3 of the piece width PW from the lower end surface 6a, the length of the lower part A of the piece 6 is 1 / piece of the piece width PW. Therefore, the clearance C1 and the clearance C2 in the non-heated state before vulcanization molding preferably satisfy the relationship of C1 ≦ C2 × 1/2. Moreover, in order to ensure the clearance C1 and to make the piece 6 slide smoothly, it is preferable to satisfy the relationship of C1 ≧ C2 × 0.2.

  In the process of raising the temperature of the mold and shifting from the non-heated state to the heated state, the piece 6 is thermally expanded, the clearance between the fitting groove 9 and the rail 8 is reduced, and the lower side surfaces 9a and 8a are mutually connected. Surface contact. In the present embodiment, as shown in FIG. 4, the lower side surface 9a of the fitting groove 9 and the lower side surface 8a of the rail 8 are both formed along the radial direction (left-right direction in FIG. 4). The pressing force when they are in surface contact only acts in the width direction WD. As a result, the radial displacement of the piece 6 due to the pressing force can be prevented, and galling can be effectively prevented.

  In the present embodiment, since the piece 6 has an undivided integrated structure in the width direction WD, the number of parts can be reduced as compared with a piece having a divided structure as described later. In addition, the piece 6 having such an integrated structure is inclined with respect to the shape elongated in the width direction WD particularly when the aspect ratio (length in the circumferential direction / length in the width direction) is approximately 0.2 or less. As it is easy, according to the mold, it is possible to prevent galling by performing the above-described action.

  If the mold is repeatedly used, the contact surface between the piece 6 and the case 7 may be deformed or consumed, and the trace may become resistance and cause galling. Therefore, it is effective to perform a process for improving the slidability of the piece 6 on at least one of the contact surface of the piece 6 and the contact surface of the case 7. The contact surface of the piece 6 corresponds to the entire back surface including the lower end surface 6 a and the upper end surface 6 b of the piece 6, and the contact surface of the case 7 corresponds to the entire inner surface of the case 7.

  In the present embodiment in which the piece 6 is softer than the case 7, surface treatment for improving the sliding property by increasing the hardness of the contact surface of the piece 6 is suitable as a process for improving the sliding property of the piece 6. Is a process of coating a high hardness material by plating or thermal spraying. Alternatively, it is also conceivable to attach a sliding material such as oilless metal to the contact surface of the piece 6.

  The present invention is not limited to the embodiments described above, and various improvements and modifications can be made without departing from the spirit of the present invention, and the shape of the pieces and the case may be changed as appropriate. In addition, a method of dividing the pieces into curved surfaces in consideration of the uneven shape of the molding surface 1a, and a method of adjusting the gap between the pieces using the biasing force of the elastic member interposed between the pieces can be appropriately employed. is there.

[Other Embodiments]
(1) In the sector 5 shown in FIG. 6, two rails 8 are provided on the inner surface of the case 7, and the fitting groove 9 and the rail 8 are fitted at two places in the width direction WD. In this case, from the viewpoint of accurately suppressing the inclination of the piece 6, the two rails 8 are arranged substantially symmetrically from the center in the width direction up and down, and the interval D is set to 1/3 to 1/2 of the piece width. Is preferred. Thereby, the positioning accuracy in the vertical direction of the piece 6 is improved, and it is possible to effectively prevent galling together with the effect of suppressing the inclination.

  In the example of FIG. 6, the clearance between the lower side surface of the upper fitting groove 9 and the lower side surface of the rail 8 in the non-heated state can be handled as the above-described clearance C1. Further, when the fitting groove 9 and the rail 8 are fitted in two places as described above, since the sliding resistance of the piece 6 tends to increase, the above-described sliding property of the piece 6 is improved. It is desirable to use the surface treatment in combination.

(2) In the present invention , the piece 6 has a single structure that is not divided in the width direction WD . Piece applied to that case of divided construction in the width direction WD, it is preferable to rails and fitted in divided respectively, if the sector 5 shown in FIG. 6, pieces of broken line BL as the dividing plane 6 Can be divided into two.

  (3) FIG. 7 shows another embodiment of the present invention in which the way of setting the clearance is changed. In this sector 5, two rails 8 are provided on the inner surface of the case 7, and the fitting groove 9 and the rail 8 are fitted at two locations in the width direction WD. The lower side surface 9a of the upper fitting groove 9 shown enlarged in the upper left is located above the center 6c in the width direction of the piece 6, and the lower side surface 9a of the lower fitting groove 9 shown enlarged in the lower left. Is positioned below the center 6 c in the width direction of the piece 6.

  In the posture in which the width direction WD is directed upward and downward, the piece 6 is moved downward by gravity, and the upper side surface 9b of the lower fitting groove 9 contacts the upper side surface 8b of the rail 8. At this time, in the non-heated state before vulcanization molding, the clearance C3 between the lower side surface 9a of the upper fitting groove 9 and the lower side surface 8a of the rail 8, the upper end surface 6b of the piece 6, and the upper end portion of the case 7 Clearance C4 between the inner surface 7b of the piece 6, clearance C5 between the lower end surface 6a of the piece 6 and the inner surface 7a of the lower end portion of the case 7, the lower side surface 9a of the lower fitting groove 9 and the lower side surface of the rail 8 A clearance C6 is provided between 8a and 8a.

  In this mold, C3 is set to be smaller than C4 and C5 and C6 is set to be larger than C4 and C5 in an unheated state. For this reason, in the process of shifting to the heating state at the time of vulcanization molding, the clearance C3 disappears first, and the piece 6 has the upper side surface 9b of the lower fitting groove 9 and the lower side surface 9a of the upper fitting groove 9 The center portion of the piece 6 (the portion extending over the gap G) is fixed. In this way, by fitting the central portion ahead of the entire portion of the piece 6, the parallelism between the adjacent pieces 6 can be accurately and quickly maintained, and galling can be effectively prevented.

  If the clearance C3 disappears, then the clearances C4 and C5 disappear and the piece 6 is strongly fitted to the case 7. At this time, if C5 is smaller than C4, the space between the lower side surface 9a and the lower end surface 6a of the upper fitting groove 9 is tightened, and thereafter the space between the upper side surface 9b and the upper end surface 6b of the lower fitting groove 9 Since it is tightened, the fixing of the piece 6 is easy to be stabilized. C5 may be larger than C4. Since the clearance C6 has not yet disappeared when the clearances C4 and C5 disappear, the parallelism of the piece 6 is not affected. Thereafter, when the thermal expansion of the piece 6 is settled, the gap between the pieces is determined.

  In order to maintain the parallelism between the pieces 6 accurately when the clearance C3 disappears, it is measured as the distance in the width direction from the upper side surface 9b of the lower fitting groove 9 to the lower side surface 9a of the upper fitting groove 9. The rail interval G is in the range of 1/4 to 3/4 of the case inner surface width measured as the distance in the width direction from the inner surface 7a of the lower end portion of the case 7 to the inner surface 7b of the upper end portion in the non-heated state. Is preferred. The sector 5 can be configured in the same manner as the sector shown in the above-described embodiment except for the configuration described above.

  In order to specifically show the configuration and effects of the present invention, the occurrence of burrs caused by rubber flowing into the gaps between the pieces was investigated using a mold of tire size 235 / 35R19, which will be described.

  The state of occurrence of burrs was evaluated by two samples: quantity determination and uniformity determination with 6 samples. In the quantity determination, the reciprocal number was calculated by counting the places where the protruding height of the burr from the tread surface exceeded 1.5 mm. In uniformity judgment, the burr protrusion height exceeds 1.5 mm in either the left or right shoulder area (if the parallelism between pieces collapses, the burr protrusion is maximum in the shoulder area). And the reciprocal number was calculated. In any case, the result of Comparative Example 1 is evaluated as 100, and the larger the value, the more the occurrence of burrs is suppressed.

Comparative Examples 1-4
As shown in FIG. 8, a mold that did not take any particular measures to suppress the inclination of the piece was designated as Comparative Example 1. A mold having the same structure as Comparative Example 1 was used as Comparative Example 2 except that a cylindrical pin protruding from the back of the piece was fitted into a recess provided on the inner surface of the case. Furthermore, a mold having the same structure as Comparative Example 1 was used as Comparative Example 3, except that the piece was divided into two in the width direction. A mold having the same structure as that of Example 1 described below was used as Comparative Example 4 except that the clearance C1 was set to 0.3 mm, the clearance C2 was set to 0.1 mm, and C1> C2.

Examples 1-3
As shown in FIGS. 3 to 5, Example 1 is a mold having a structure in which a rail protruding from the inner surface of a case is fitted into a fitting groove recessed in the back of a piece. In Example 1, the clearance C1 was 0.1 mm, the clearance C2 was 0.3 mm, and C1 <C2. In addition, as shown in FIG. 7, the number of rails is two, the clearance C3 is 0.1 mm, the clearance C4 is 0.17 mm, the clearance C5 is 0.13 mm, and the clearance C6 is 0.2 mm. A mold having the same structure as in Example 1 was designated as Example 2. Furthermore, a mold having the same structure as that of Example 2 was used in Example 3 except that the contact surface of the piece was subjected to chrome plating. The evaluation results are shown in Table 1.

  As shown in Table 1, in Examples 1 to 3, the occurrence of burrs is suppressed compared to Comparative Examples 1 to 4. In Example 2, although the frequency of occurrence of burrs slightly increased compared to Example 1, since the parallelism of the pieces is good, good results are obtained in the uniformity determination. Moreover, in Example 3, since the slidability of the piece was improved by performing the chrome plating, the frequency of generating burrs is reduced compared to Example 2.

5 sector 6 piece 6a piece lower end surface 6b piece upper end surface 6c piece width center 7 case 7a case lower end inner surface 7b case upper end inner surface 8 rail 8a rail lower side 8b rail upper side 9 fitting Joint groove 9a Lower side 9b of fitting groove Upper side C1 to C6 of fitting groove Clearance

Claims (4)

In a tire mold comprising a plurality of pieces arranged in the circumferential direction, and a case in which the plurality of pieces are mounted on the inner surface side, the sector contacting the tread surface of the tire set with the width direction set up and down,
The piece has a monolithic structure that is not divided in the width direction, and is made of a material having a larger coefficient of thermal expansion than the case.
A rail extending in the circumferential direction protrudes on the inner surface of the case, and a fitting groove for fitting with the rail is recessed on the back surface of each piece, and a lower side surface of the fitting groove is below the rail. It is formed to be able to contact the side surface,
When the lower end surface of the piece mounted on the case is brought into contact with the inner surface of the lower end portion of the case, in a non-heated state before vulcanization molding, a clearance C1 between the side surface, the clearance C2 and are provided between the upper end surface and the inner surface of the upper portion of the casing of the piece, rather smaller than C1 is C2,
When shifting to the heating state at the time of vulcanization molding, the clearance C1 disappears first, and then the clearance C2 disappears, so that the entire portion of the piece precedes the lower end surface of the piece and below the fitting groove. A tire mold characterized in that a lower portion extending to a side surface is configured to be tightly fitted .   The tire mold according to claim 1, wherein the fitting groove and the rail are fitted at one place in the width direction, and a lower side surface of the fitting groove is positioned above a center in the width direction of the piece. In a tire mold comprising a plurality of pieces arranged in the circumferential direction, and a case in which the plurality of pieces are mounted on the inner surface side, the sector contacting the tread surface of the tire set with the width direction set up and down,
The piece has a monolithic structure that is not divided in the width direction, and is made of a material having a larger coefficient of thermal expansion than the case.
A rail extending in the circumferential direction protrudes on the inner surface of the case, and a fitting groove for fitting with the rail is recessed on the back surface of each piece, and a lower side surface of the fitting groove is below the rail. It is formed to be able to contact the side surface,
The fitting groove and the rail are fitted at two locations in the width direction, and the lower side surface of the upper fitting groove is positioned above the center in the width direction of the piece, and the lower fitting portion The lower surface of the groove is located below the center in the width direction of the piece,
When the upper side surface of the lower fitting groove is in contact with the upper side surface of the rail in a non-heated state before vulcanization molding, it is between the lower side surface of the upper fitting groove and the lower side surface of the rail. Clearance C3, clearance C4 between the upper end surface of the piece and the inner surface of the upper end portion of the case, clearance C5 between the lower end surface of the piece and the inner surface of the lower end portion of the case, and the lower portion the lower surface of the fitting groove and the clearance C6 between the lower surface of the rail is provided, C3 is smaller than the C4 and C5, C6 is much larger than the C4 and C5,
When shifting to the heating state at the time of vulcanization molding, the clearance C3 disappears first, and then the clearances C4 and C5 disappear, so that from the upper surface of the lower fitting groove ahead of the entire part of the piece. A tire mold characterized in that a center portion extending to the lower surface of the upper fitting groove is tightly fitted. The tire mold according to any one of claims 1 to 3, wherein a lower side surface of the fitting groove and a lower side surface of the rail are formed along a radial direction.

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