JP5513345B2 - Vulcanization mold for spike tire and spike tire - Google Patents

Description

  The present invention provides a vulcanization mold for spike tire that forms a hole (spike pin insertion hole) for driving a spike pin into a tread portion when vulcanizing a raw tire, and a vulcanization mold for spike tire. With regard to the manufactured spike tire, in particular, it is intended to prevent cracks from occurring around the spike pin driving hole due to die cutting.

  Spike tires with spike pins embedded in the land portion of the tread are known as tires for snow and ice that have been developed to improve the ride comfort when wearing chains and the inconvenience of attaching and detaching chains. As shown in FIG. 6A, the spike pin P includes a columnar body P1, a tip P2 disposed at the tip of the body P1, and a retaining pin provided on the base end side of the body P1. The one provided with the flange P3 is used.

  When such a spike pin is driven into a spike pin driving hole that has been opened in advance on the surface of the land portion of the tread portion, the diameter of the spike pin driving hole 30 is the opening thereof as shown in FIG. If the distance is constant from the end to the bottom, the force to hold the spike pin P by the inner wall surface of the spike pin driving hole 30 is weak, and there is a concern that the spike pin may fall off during traveling.

  In order to prevent the spike pin from falling off, Patent Document 1 discloses that a step is formed by providing an enlarged diameter portion near the bottom of the spike pin driving hole, and the flange of the spike pin is engaged with the step. Thus, a technique for increasing the holding force of the spike pin is disclosed.

JP 2010-111130 A

  By the way, as shown in FIG. 7, the spike pin driving hole 50 is formed by a protrusion 41 for forming a spike pin driving hole provided on the mold side when the raw tire is vulcanized (in addition, each protrusion includes a tip side portion. Is formed as a vulcanization mold, facing the tread portion of the green tire inserted during vulcanization, A plurality of sector molds 40 arranged along a direction, and an annular mold is formed by the plurality of sector molds 40. As seen in a circumferential section of the annular mold, When the peripheral surface 40a is arcuate and a vulcanization mold is used in which a plurality of protrusions 41 projecting radially inward of the annular mold are provided on the inner peripheral surface 40a of each sector mold 40. Each sector Since the mold 2 moves along the radial line m passing through the center position in the circumferential direction of the inner peripheral surface 40a and the center position of the annular mold during die cutting, the mold 2 moves to the inner peripheral surface 40a of each sector mold 40. Of the protrusions 41 arranged, the tip side part (the bulging part 41a) of the protrusion 41 at a position away from the position on the radial line m is caught around the spike pin driving hole 50 and cracks (cracks) ) Cr may be generated. Such a crack Cr may develop during traveling and eventually cause the spike pin P to drop off.

  Therefore, the present invention relates to a spike tire vulcanization mold that forms a step for hooking a flange of a spike pin in the vicinity of the bottom of the spike pin driving hole. It is an object of the present invention to provide a vulcanization mold for spike tires and a spike tire having a good spike holding force capable of preventing cracks from being formed around pin driving holes.

  The present invention has been made to solve the above-mentioned problems, and the vulcanization mold for spike tire according to the present invention is opposed to the tread portion of a raw tire inserted during vulcanization, along the circumferential direction. A plurality of sector molds are provided, an annular mold is formed by the plurality of sector molds, and an inner peripheral surface of each sector mold has an arc shape when viewed in a circumferential section of the annular mold. A plurality of spike pin driving hole forming projections projecting radially inward of the annular mold are disposed on the inner peripheral surface of each sector mold, and each sector mold is arranged in the circumferential direction of the inner peripheral surface. A vulcanization mold for spike tires that is movable along a radial line passing through a center position and a center position of the annular mold, and that allows the diameter of the annular mold to be increased or decreased by the movement of the sector mold. The protrusion has a bulging portion having a diameter larger than that of the proximal end portion at the distal end side portion, and the position on the radial line among the protrusion portions disposed on the inner peripheral surface of each sector mold. The bulging portion of the tip side portion of the protrusion located at a position away from the first outer surface portion, which is an outer surface portion on the side near the plane including the radial line, as seen in the circumferential cross section of the annular mold, A second outer surface portion that is an outer surface portion on the side far from the flat surface, and a first bulging distance that is a distance from the first outer surface portion to the axis of the protruding portion is from the second outer surface portion to the protrusion. It is smaller than the 2nd bulging distance which is the distance to the said axis line of a part. The “first bulging distance” here refers to an imaginary straight line passing through a point of the first outer surface portion that is farthest from the extending axis of the protrusion and parallel to the extending axis, and the extending axis. The “second bulging distance” is an imaginary straight line passing through a point of the second outer surface portion farthest from the extending axis of the protrusion and parallel to the extending axis. , The distance formed by the extending axis.

  In such a vulcanization mold for spike tires, the first bulge distance is set to be greater than the second bulge distance at the bulge portion formed at the tip side portion of the protrusion at a position away from the position on the radial line. Therefore, when the mold is released after the tire is vulcanized, the first outer surface portion of the protruding portion of the protruding portion is hooked (resisting) around the spike pin driving hole formed by the protruding portion. And the occurrence of cracks around the spike pin driving hole can be prevented. In addition, the protruding portion is not a straight shape (a shape having a constant diameter from the base to the tip), but a bulging portion is formed on the tip side portion, so that the spike pin is inserted into the spike pin driving hole formed by the protrusion. The level | step difference which a flange latches can be formed and the spike pin holding force excellent in the spike tire can be provided. More specifically, since the second bulge distance is made larger than the first bulge distance, the inner surface portion of the expanded portion of the spike pin driving hole corresponding to the second outer surface portion (hereinafter also referred to as the second inner surface portion). Is larger than the recess of the inner surface portion (hereinafter also referred to as the first inner surface portion) of the enlarged diameter portion of the spike pin driving hole corresponding to the first outer surface portion. The spike pin holding force reduced by the reduction of the dent of the portion can be compensated by the second inner surface portion, and a spike tire capable of exhibiting sufficient holding force of the spike pin can be molded.

  Therefore, according to the vulcanization mold for spike tire according to the present invention, the vulcanization mold for spike tire that forms a step for hooking the flange of the spike pin in the vicinity of the bottom of the spike pin driving hole, By optimizing the shape of the bulging portion, it is possible to prevent cracks from being formed around the spike pin driving hole by the protrusion due to die cutting. Further, the spike tire formed by the vulcanization mold for spike tire according to the present invention exhibits a good holding force of the spike pin and can prevent the spike pin from falling off.

  In the vulcanization mold for spike tire according to the present invention, the protrusions disposed on the inner peripheral surface of the sector mold are separated from each other by a distance from the plane including the radial line. It is preferable to reduce the second bulging distance.

  In the vulcanization mold for spike tire according to the present invention, each of the first outer surface portion and the second outer surface portion is constituted by a single arc, and the curvature of the first outer surface portion is second. The curvature is preferably smaller than the curvature of the outer surface portion.

  Further, in the vulcanization mold for spike tire according to the present invention, the protrusions arranged on the inner peripheral surface of each sector mold are arranged at positions far from the plane including the radial line. It is preferable to increase the second bulging distance.

  The spike tire of the present invention is formed by driving a spike pin with a flange into a spike pin driving hole of a tire vulcanized and molded using the vulcanization mold for spike tire described in any of the above. .

  According to the present invention, there is provided a vulcanization mold for a spike tire capable of preventing cracks from being formed around the spike pin driving hole due to the protrusion that forms the spike pin driving hole due to die cutting. In addition, it is possible to provide a spike tire having a good spike pin holding force.

It is principal part sectional drawing which shows the vulcanization die for spike tires applied to this invention. It is a top view of a plurality of sector molds applied to this invention, and an annular mold formed by the sector mold. It is sectional drawing along the circumferential direction which shows the sector mold of one Embodiment according to this invention. It is sectional drawing which shows the spike pin driving hole formed using the sector mold of FIG. It is sectional drawing along the circumferential direction which shows the sector mold of other embodiment according to this invention. (A) is a perspective view of a spike pin with a flange to be driven into a spike pin driving hole of a spike tire according to the present invention, and (b) is a cross section showing a conventional spike pin driving hole in which the shape of the hole is straight FIG. (A) is principal part sectional drawing along the circumferential direction which showed a mode that the conventional sector mold was released from the vulcanized tire, (b) is an enlarged view of (a), (c) ) Is a plan view showing a tread portion of a spike tire vulcanized and molded using a vulcanization mold having the sector mold of (a).

  Embodiments of the present invention will be described below with reference to the drawings.

  A spike tire vulcanization mold (hereinafter referred to as “vulcanization mold”) 1 of this embodiment is a sectional type mold divided into a plurality of parts in the circumferential direction, as shown in FIGS. A plurality of (9 in this case) sector molds 2 are provided in the circumferential direction so as to face the tread portion of the raw tire to be charged during vulcanization. Each sector mold 2 has an arc-shaped inner peripheral surface 2a, and forms an annular mold 3 in cooperation with each other. Each sector mold 2 is held from the outside in the radial direction by a plurality of segments 4. The segment 4 has an inclined surface (tapered surface) formed on the outer peripheral surface so as to taper upward.

  A pair of side molds 6 and 7 are arranged on the inner side in the radial direction of the sector mold 2 so as to face each other in the vertical direction and each have a molding surface for molding a side portion of the raw tire.

  An outer ring 8 that presses each segment 4 inward in the radial direction is disposed outside the segment 4 in the radial direction. The outer ring 8 has an inner peripheral surface tapered so as to increase in diameter as it goes downward, and slides with the outer peripheral surface of the segment 4.

  When the raw tire is vulcanized, when the raw tire is inserted into the vulcanizing mold 1 and the outer ring 8 is lowered, the vulcanizing mold 1 having the above configuration is an inner peripheral surface of the outer ring 8. Becomes a thrust surface and moves the segment 4 inward in the radial direction. As the segment 4 moves inward in the radial direction, each sector mold 2 becomes a radial line (the center in the circumferential direction of the inner peripheral surface 2a of the sector mold 2). The position of the green tire moves inward in the radial direction along the imaginary straight line (m) passing through the position and the center position of the annular mold 3 and presses the tread portion of the green tire. Next, the vulcanization mold 1 is heated with a heat medium having a predetermined temperature and pressure to vulcanize the green tire. After the vulcanization is completed, the outer ring 8 is raised and each sector mold 2 is moved radially outward along the radial line m. Thereby, the vulcanized tire can be taken out from the vulcanization mold 1.

  Here, on the inner peripheral surface 2a of each sector mold 2, as shown in FIG. 3, a plurality of spikes (here, 100 to 130 spikes in each sector mold) projecting inward in the radial direction of the annular mold 3. A protrusion 10 for forming a pin driving hole is provided. The protrusions 10 are detachably held on the sector mold 2, and the number of protrusions 10 can be appropriately changed according to the number of spike pin driving holes 20 (see FIG. 4) required. In FIG. 3, for the convenience of explanation, the number of protrusions is reduced.

  As shown in FIG. 3, each protrusion 10 includes a proximal end portion 10a extending linearly from the inner peripheral surface 2a of the sector mold 2 with the same diameter, and a distal end portion 10b extending from the proximal end portion 10a to the distal end side. It consists of and. A bulging portion 11 having a diameter larger than that of the proximal end portion 10a is formed in the distal end portion 10b. Further, among the protrusions 10 arranged on the inner peripheral surface 2 a of each sector mold 2, the bulging part 11 of the protrusion 10 at a position away from the position on the radial line m is the circumferential direction of the annular mold 3. The first outer surface portion is composed of a first outer surface portion 11a which is an outer surface portion on the side close to the plane including the radial line m and a second outer surface portion 11b which is an outer surface portion on the side far from the plane as viewed in cross section. The first bulging distances X1, X2, X3, X4,..., Xn, which are the maximum distances from 11a to the axis s of the protrusion 10, are the maximum distances from the second outer surface portion 10b to the axis s of the protrusion 10. Are set smaller than the second bulging distances Y1, Y2, Y3, Y4,. That is, in the protrusion 10 at a position away from the position on the radial line m, the bulging amount of the first outer surface portion 11a is larger than the bulging amount of the second outer surface portion 11b when viewed in the circumferential cross section of the annular mold 3. It is getting smaller.

  Further, in this embodiment, the protrusions 10 arranged on the inner peripheral surface 2a of each sector mold 2 are more bulging the protrusions 10 arranged farther from the plane including the radial line m. The distances X1, X2, X3, X4,..., Xn are set small. That is, the relationship X1> X2> X3> X4> Xn is satisfied.

  Moreover, in this embodiment, the first outer surface portion 11a and the second outer surface portion 11b are each configured by a single arc, and the curvature of the first outer surface portion 11a is set smaller than the curvature of the second outer surface portion 11b. ing.

  In the vulcanization mold 1 having such a sector mold 2, the first bulging distances X1, X2, and the like at the distal end portion 11 of the protrusion 10 at a position away from the position on the radial line m, Since X3, X4,..., Xn are smaller than the second bulging distances Y1, Y2, Y3, Y4,..., Yn, a protrusion is formed when the mold 1 is released after vulcanization of the tire. The hook (resistance) of the first outer surface portion 11a of the tip end portion 11 of the portion 10 around the spike pin driving hole 20 formed by the protrusion 10 is reduced, and a crack is generated around the spike pin driving hole 20 Can be prevented.

  In addition, since the protruding portion 10 is not formed in a straight shape (a shape having a constant diameter from the base to the tip), but the bulging portion 11 is formed in the tip side portion 10b, the protrusion 10 can be used as shown in FIG. A step 21 on which the flange P1 of the spike pin P is hooked can be formed in the formed spike pin driving hole 20, and a desired spike pin holding force can be applied to the spike tire 23. More specifically, since the second bulging distances Y1, Y2, Y3, Y4,..., Yn are larger than the first bulging distances X1, X2, X3, X4,. 2 Spike pin driving hole corresponding to the first outer surface portion 11a corresponding to the inner surface portion (hereinafter also referred to as second inner surface portion) 22b of the enlarged diameter portion 22 of the spike pin driving hole 20 corresponding to the outer surface portion 11b. The inner diameter portion (hereinafter also referred to as the first inner surface portion) 22a of the 20 enlarged-diameter portion 22 is larger than the recess of the first inner surface portion 22a. The spike tire 23 that can be compensated by the inner surface portion 22b and can exhibit a sufficient holding force of the spike pin can be molded.

  Therefore, according to this vulcanizing mold 1, with respect to the vulcanizing mold 1 that forms the step 21 that hooks the flange P <b> 3 of the spike pin P in the vicinity of the bottom of the spike pin driving hole 20, By optimizing the shape, it is possible to prevent cracks from being formed around the spike pin driving hole 20 by the protrusion 10 due to die cutting. Further, the spike tire 23 formed by the vulcanization mold 1 exhibits a sufficient holding force of the spike pin, and can prevent the spike pin P from falling off.

  Further, when the sector mold 2 is pulled away from the tire after vulcanization of the tire, the protrusion 10 disposed at a position farther from the plane including the radial line m has a larger angle at which the protrusion 10 is inclined with respect to the radial line m. In other words, in this embodiment, the protrusions 10 disposed on the inner peripheral surface 2a of each sector mold 2 are arranged such that the protrusions 10 disposed at positions farther from the plane including the radial line m are closer to the first swelling. Since the outgoing distances X1, X2, X3, X4,..., Xn are set small, the first outer surface portion 11a and the spike pin are driven into the protrusion 10 disposed farther from the plane including the radial line m. Resistance with the holes 20 can be reduced, and cracks can be reliably prevented from occurring in all the spike pin driving holes 20.

  Moreover, in the vulcanization mold 1 of this embodiment, since the first outer surface portion 11a and the second outer surface portion 11b are each configured by a single arc, the protrusion 10 bulges during die cutting. The resistance between the portion 11 and the spike pin driving hole 20 can be further reduced, and the occurrence of cracks around the spike pin driving hole due to die cutting can be more reliably prevented.

  FIG. 5 shows another sector mold 2 applicable to the present invention. In this example, the protrusions 10 disposed on the inner peripheral surface 2a of each sector mold 2 are arranged such that the protrusions 10 disposed at a position farther from the plane including the radial line m are closer to the second bulging distance Y1, Y2, Y3, Y4,..., Yn are set large. Further, the first bulging distances X1, X2, X3, X4,..., Xn and the second bulging distance Y1, between the protrusions 10 disposed on the inner peripheral surface 2a of each sector mold 2, The sum of Y2, Y3, Y4,..., Yn is set to be approximately equal. That is, the relationship X1 + Y1 = X2 + Y2 = X3 + Y3 = X4 + Y4 = Xn + Yn is satisfied.

  According to this, as it goes to a position farther from the plane including the radial line m, the spike pin holding force by the second inner surface portion of the spike pin driving hole of the formed spike tire can be increased, and all spike pin driving holes An approximately equal spike pin holding force to 20 can be applied. In particular, the first bulging distances X1, X2, X3, X4,..., Xn and the second bulging distances Y1, Y2 between the protrusions 10 disposed on the inner peripheral surface 2a of each sector mold 2 are. , Y3, Y4,..., Yn can be set to be approximately equal, so that even more spike pin holding force can be applied to all the spike pin driving holes 20.

  Although the present invention has been described based on the illustrated examples, the present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the claims. For example, in the above-described embodiment, The first outer surface portion and the second outer surface portion constituting the tip side portion of the protrusion are described as being formed by a single arc when viewed in the circumferential cross section of the annular mold. Each of the outer surface portions may be semi-elliptical.

  Applying the present invention, in each protrusion, the first bulge distance that is the distance from the first outer surface portion to the axis of the protrusion is the second bulge that is the distance from the second outer surface portion to the axis of the protrusion. A vulcanization mold of an embodiment having a sector mold (FIG. 3) smaller than the distance, and a first bulging distance that is a distance from the first outer surface portion to the axis of the protrusion in each protrusion, (2) A spike tire is vulcanized using a vulcanization mold of a comparative example having a sector mold (not shown) having the same second bulging distance as the distance from the outer surface portion to the axis of the protrusion. When the occurrence of cracks around the pin driving hole was examined, when the comparative vulcanization mold was used, the ratio of the spike pin driving hole where the crack occurred to the total spike pin driving hole was 7 to 18%. In contrast, the vulcanization mold of the example When used, for all studs driving holes, the ratio of the generated studs driving holes of cracks was 0%.

  Thus, according to the present invention, a spike tire vulcanization mold for forming a step for hooking the flange of the spike pin near the bottom of the spike pin driving hole is used to increase the spike by the protrusion that forms the spike pin driving hole due to die cutting. It was possible to prevent cracks from forming around the pin driving hole.

DESCRIPTION OF SYMBOLS 1 Spike tire vulcanization mold 2 Sector mold 2a Inner peripheral surface of sector mold 3 Ring mold 4 Segment 6, 7 Side mold 8 Outer ring 10 Protrusion 10a Proximal end portion 10b Protrusion end portion DESCRIPTION OF SYMBOLS 11 Swelling part 11a 1st outer surface part 11b 2nd outer surface part 20 Spike pin driving hole 21 Step difference of spike pin driving hole 22 Diameter expansion part of spike pin driving hole 22a 1st inner surface part 22b 2nd inner surface part 23 Spike tire m Radial Wire P Spike pin P3 Spike pin flange

Claims (5)

A plurality of sector molds arranged in the circumferential direction facing the tread portion of the raw tire to be charged at the time of vulcanization, and forming the annular mold by the plurality of sector molds, As seen from the circumferential cross section of the ring mold, the inner peripheral surface of each sector mold has an arc shape, and a plurality of spike pin driving holes projecting radially inward of the annular mold on the inner peripheral surface of each sector mold Protrusions for forming are disposed, and each sector mold is movable along a radial line passing through the center position in the circumferential direction of the inner peripheral surface and the center position of the annular mold, and by the movement of the sector mold In the vulcanization mold for spike tires that enables expansion and contraction of the diameter of the annular mold,
The protruding portion has a bulging portion having a larger diameter than the proximal end portion at the distal end portion,
Of the protrusions disposed on the inner peripheral surface of each sector mold, the bulging portion of the tip side portion of the protrusion located at a position away from the position on the radial line is seen in the circumferential section of the annular mold. A first outer surface portion that is an outer surface portion on a side close to a plane including the radial line, and a second outer surface portion that is an outer surface portion on a side far from the plane, and from the first outer surface portion, A first bulging distance, which is a distance to the axis, is smaller than a second bulging distance, which is a distance from the second outer surface portion to the axis of the projection, .   The protrusions disposed on the inner peripheral surface of each sector mold are such that the protrusions disposed at positions farther from a plane including the radial line reduce the first bulge distance. Vulcanization mold for spike tires.   The spike according to claim 1 or 2, wherein each of the first outer surface portion and the second outer surface portion is configured by a single arc, and the curvature of the first outer surface portion is smaller than the curvature of the second outer surface portion. Tire vulcanization mold.   The protrusions disposed on the inner peripheral surface of each sector mold increase the second bulging distance as the protrusion is disposed farther from the plane including the radial line. The described vulcanization mold for spike tires.   A spike tire obtained by driving a spike pin with a flange into a spike pin driving hole of a tire vulcanized and molded using the vulcanization mold for spike tire according to any one of claims 1 to 4.

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