JP2007203566A - Molding process and apparatus for forming rubber layer for tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance tire quality by ejecting the air involved in when a rubber strip 21 is spirally ejected. <P>SOLUTION: When a molding drum revolves to a circumferential axis, the rubber strip 21 is applied traversely and rolled to the outside of a molding drum spirally, and a tread as a rubber layer for the tire is fabricated. Here, at the time of feeding or the rubber strip 21 to the molding drum, a perforation 47 which penetrates between the inside and the outside surfaces by a punching needle 45 is formed in an auxiliary roller 42 which carries out rolling contact to this rubber strip 21 is formed, which results in that even if air is involved in between the rubber strip 21, the molding drum, etc. during the above-mentioned rolling, the air is ejected to the outside through the above-mentioned perforation 47. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

    The present invention relates to a tire rubber layer forming method and apparatus for forming a tire rubber layer such as a tread by winding a rubber strip in a spiral shape.

As a conventional method and apparatus for forming a tire rubber layer, for example, a tread, one described in Patent Document 1 below is known.
JP 2003-236950 A

  This is provided with a molding drum rotatable around an axis, and a supply means for feeding a rubber strip made of unvulcanized rubber while traversing the rotating molding drum. By supplying to the rotating forming drum while traversing by means (moving in the axial direction of the forming drum), the belt layer is interposed on the outside of the forming drum and wound many times in a spiral shape. Thus, a tire rubber layer as a tread is molded.

    However, in such a conventional method and apparatus for molding a rubber layer for a tire, when the rubber strip is wound around the outside of the molding drum, the rubber strip and the molding drum (there may be a belt layer or a rubber strip). However, there is a problem that the air that is involved in this way deteriorates the tire quality and causes the occurrence of cracks. In addition, when air is entrained as described above, the cross-sectional shape of the tire rubber layer on both sides of the tire equator is different, which causes a problem that tire uniformity is deteriorated.

  An object of the present invention is to provide a method and an apparatus for forming a tire rubber layer that can improve the tire quality by discharging the entrained air.

    The first object is to supply a rubber strip made of unvulcanized rubber to a molding drum rotating about an axis and to wind the rubber strip spirally around the rubber strip for tires. In the tire rubber layer molding method in which a layer is molded, a tire rubber layer in which a through-hole penetrating between the front and back surfaces is formed by a perforating needle in the supplied or wound rubber strip. Depending on the molding method,

  Second, a tire molding drum rotatable around an axis and a rubber strip made of unvulcanized rubber are fed to the rotating molding drum while traversing, and the rubber strip is spirally formed outside the molding drum. In a tire rubber layer molding apparatus comprising a supply means for winding and molding a tire rubber layer, a perforation roller provided with a perforation needle capable of rolling contact with the rubber strip and inserted into the rubber strip on the outer periphery. It can be achieved by a tire rubber layer molding device that is installed and forms a through-hole that penetrates between the front and back surfaces of the rubber strip that has been supplied or wound by the punch needle of the punch roller. .

    When the molding drum rotates about the axis, the rubber strip is fed to the molding drum while being traversed by the supply means, and the rubber strip is spirally wound around the outer side of the molding drum to mold the tire rubber layer. Here, when a through-hole penetrating between the front and back surfaces of the rubber strip is formed by a perforation needle provided on the perforated roller that is in contact with the molding drum when it is supplied or rolled onto the wound rubber strip, Even when air is caught between the rubber strip and the forming drum at the time of winding, the air is discharged to the outside through the above-described through hole. As a result, the tire quality is improved and the occurrence of cracks is also effectively suppressed. Further, the cross-sectional shape of the tire rubber layer is approximated on both sides of the tire equator, and the tire uniformity is improved.

Moreover, if comprised as mentioned in Claim 2, 3, air can be discharged | emitted reliably, suppressing generation | occurrence | production of the bear etc. based on the rubber | gum flow shortage at the time of vulcanization.
Further, if configured as described in claim 5, air can be reliably discharged, and if configured as described in claim 6, formation of a through hole is facilitated. If comprised as described in claim | item 7, when the rubber | gum kind, thickness, etc. of a rubber strip have changed, it can cope with this easily and a through-hole can be shape | molded reliably.

Embodiment 1 of the present invention will be described below with reference to the drawings.
In FIGS. 1, 2, and 3, reference numeral 11 denotes a cylindrical molding drum that can rotate around a horizontal axis and can be expanded and contracted. When the molding drum 11 is driven by a drive motor (not shown), Rotate. Reference numeral 12 denotes a belt / tread band formed by the forming drum 11. The belt / tread band 12 is used for manufacturing a heavy-duty pneumatic radial tire mounted on, for example, a truck / bus.

  The belt tread band 12 has a cylindrical belt layer 15 affixed to the outer periphery of a forming drum 11, and this belt layer 15 supplies a plurality of belt plies 16 to a rotating forming drum 11 to supply the belt tread band 12. It is configured by sticking to the outer circumference one after another and laminating in the radial direction. Reference numeral 17 denotes a tread as a tire rubber layer disposed outside the molding drum 11 and the belt layer 15. The tread 17 and the belt ply 16 constitute the belt layer 15 described above as a whole.

  20 is an extruder installed behind the molding drum 11, from which a ribbon-like rubber strip 21 made of unvulcanized rubber having a narrow width is extruded one after another toward the molding drum 11. . The rubber strip 21 extruded from the extruder 20 travels while sequentially contacting three free-rotating rollers 22, 23, 24 installed between the extruder 20 and the molding drum 11. , Stretched by a predetermined amount.

  Reference numeral 28 denotes a support frame installed immediately after the molding drum 11. A pair of guide rails 29 extending in the front-rear direction are laid on the upper surface of the support frame 28, and these guide rails 29 are disposed above the support frame 28. A plurality of slide bearings 31 fixed to the lower surface of the horizontal lower movable plate 30 installed in the slidably engage with each other. When a driving force is applied from a driving mechanism such as a screw mechanism (not shown), the lower movable plate 30 moves in the front-rear direction while being guided by the guide rail 29 and approaches and separates from the forming drum 11.

  34 is a pair of guide rails laid on the upper surface of the lower movable plate 30 and extending in a direction perpendicular to the guide rails 29, here the axial direction of the forming drum 11, and these guide rails 34 include the lower movable plate 30 of the lower movable plate 30. A plurality of slide bearings 36 fixed to the lower surface of a horizontal upper movable plate 35 installed above are slidably engaged. The upper movable plate 35 moves along the axis of the forming drum 11 while being guided by the guide rail 34 when a driving force is applied from a driving mechanism such as a screw mechanism (not shown).

  Reference numeral 40 denotes a pair of vertically extending support plates whose lower ends are fixed to the upper movable plate 35, and a stitcher roll 41 having an axis parallel to the axis of the forming drum 11 is rotatably supported by these support plates 40. ing. An auxiliary roller 42 is rotatably supported by the support plate 40 immediately above the stitcher roll 41. The axis of the auxiliary roller 42 is parallel to the axis of the stitcher roll 41. Since the rubber strip 21 after passing through the roller 24 is supplied between the stitcher roll 41 and the auxiliary roller 42, the rubber strip 21 in the middle of being supplied to the forming drum 11 is in rolling contact with the auxiliary roller 42. Will do.

  Here, the rubber strip 21 supplied between the stitcher roll 41 and the auxiliary roller 42 as described above is pressed against the stitcher roll 41 by the auxiliary roller 42 in the vicinity of the contact start point with respect to the stitcher roll 41, and then the stitcher roll 41 It is hung around. Thereafter, when the rubber strip 21 reaches the vicinity of the separation point that is approximately 1/4 turn away from the contact start point, the rubber strip 21 is pressed against the forming drum 11 by the stitcher roll 41. As a result, the rubber strip 21 is separated from the stitcher roll 41 at the separation point (winding point K), while the forming drum 11 (the belt layer 15 and the rubber strip 21 is interposed therebetween) at the winding point K. And the winding is started.

  In this way, when the rubber strip 21 is pressure-bonded to the outside of the molding drum 11, the molding drum 11 is rotated around the axis, and the upper movable plate 35, the support plate 40, the stitcher roll 41, and the auxiliary roller 42 are driven by the drive mechanism. Is integrally moved in the axial direction of the molding drum 11 along the guide rail 34, the rubber strip 21 is traversed in the axial direction of the molding drum 11, and spirally wound around the outer side of the molding drum 11. Turned.

  At this time, the outer diameter of the molding drum 11 and the like varies depending on the position in the axial direction because the belt layer 15 is attached to the outside of the molding drum 11, and therefore the lower movable plate 30 and the upper movable plate 35 are driven by the drive mechanism. The stitcher roll 41 and the auxiliary roller 42 are integrally moved in the front-rear direction along the guide rail 29 so that the rubber strip 21 is always pressure-bonded to the molding drum 11 and the like by the stitcher roll 41.

  Thus, when the rubber strip 21 is wound around the outside of the molding drum 11 a predetermined number of times, the tread 17 made of the rubber strip 21 is molded on the outside of the molding drum 11. The above-described drive mechanism, lower and upper movable plates 30, 35, support plate 40, and stitcher roll 41 as a whole supply a rubber strip 21 made of unvulcanized rubber while traversing the rotating molding drum 11, The rubber strip 21 is spirally wound around the outside of the molding drum 11 to constitute a supply means 43 for molding the tread 17 as a tire rubber layer.

  Here, as described above, when the tread 17 is formed by spirally winding the rubber strip 21 around the outside of the forming drum 11, the rubber strip 21 and the forming drum 11 are wound when the rubber strip 21 is wound. In some cases, air is caught between the tires and the like, and in this case, the tire quality is deteriorated.

  Therefore, between the extruder 20 and the molding drum 11 or around the molding drum 11, in this embodiment, the vicinity of the winding point K around the molding drum 11 of the rubber strip 21, more specifically, slightly upstream from the winding point K. The auxiliary roller 42 as a perforating roller is arranged on the side, and the auxiliary roller 42 is supplied to the molding drum 11 or is wound around the molding drum 11, and in this embodiment, the rubber strip 21 is supplied. In addition, a large number of perforating needles 45 extending in the radial direction and having a radial length L equal to or greater than the thickness t of the rubber strip 21 are provided substantially uniformly on the outer periphery thereof.

  Thus, when the rubber strip 21 passes between the stitcher roll 41 and the auxiliary roller 42 immediately before being wound around the molding drum 11, the punching needle 45 is attached to the rubber strip 21 by the rotation of the auxiliary roller 42. The rubber strip 21 is pushed in one after another, and a plurality of through holes 47 penetrating between the front and back surfaces are formed in the rubber strip 21. As a result, even if air is caught between the rubber strip 21 and the molding drum 11 or the like when the rubber strip 21 is wound as described above, the air is discharged to the outside through the through hole 47 described above.

  As a result, the tire quality is improved and the occurrence of cracks is also effectively suppressed, and the cross-sectional shape of the tread 17 is approximated on both sides of the tire equator, thereby improving the tire uniformity. In addition, the restriction of the winding pitch at the time of winding the rubber strip 21 becomes loose, and the degree of freedom of winding becomes high. Further, as described above, if the through hole 47 is formed immediately before the rubber strip 21 is wound around the molding drum 11, the crushing of the through hole 47 is effectively suppressed, and the discharge of air is ensured. Become. Furthermore, if the perforation needle 45 is provided on the outer periphery of the auxiliary roller 42, the perforation needle 45 can be inserted into the rubber strip 21 one after another by the rotation of the auxiliary roller 42, and the through hole 47 can be formed. improves.

  Here, the perforation needle 45 has the same cross-sectional shape from the base end to the front end on the auxiliary roller 42 side, but in this way, the cross-sectional area of the through hole 47 does not change at any depth position. The air can be reliably discharged. Further, as shown in FIG. 4, the perforating needle 45 can be tapered from the proximal end on the auxiliary roller 42 side toward the distal end. In this case, the deeper the position, the smaller the cross-sectional area of the through hole 47 becomes. Therefore, the insertion of the perforation needle 45 into the rubber strip 21 is facilitated, and the formation of the through hole 47 can be facilitated.

  The cross-sectional shape of the piercing needle 45 (through hole 47) can be a circle, an ellipse, or a polygon such as a quadrangle or a hexagon. Further, the perforating needles 45 can be arranged in a grid pattern or a zigzag pattern on the outer periphery of the auxiliary roller 42. With this arrangement, the through holes 47 formed in the rubber strip 21 are similarly formed. It becomes a grid-like arrangement or a staggered arrangement.

Furthermore, the cross-sectional area of the through-hole 47 formed by the perforation needle 45 is constant as described above, and the cross-sectional area at the minimum cross-sectional position of the through-hole 47 is different depending on the depth position. The area is preferably in the range of 1 to 3 mm ² . The reason for this is that if the cross-sectional area is less than 1 mm ² , the entrained air may not be sufficiently discharged, while if it exceeds 3 mm ² , bears or the like may occur due to insufficient rubber flow during vulcanization. This is because air can be reliably discharged while suppressing the generation of bears and the like based on insufficient rubber flow during vulcanization.

Further, it is preferable that only 1 to 5 through-holes 47 are formed in the rubber strip 21 per 1 cm ² . The reason is that if the number of through-holes 47 per 1 cm ² is less than 1, the entrained air may be insufficiently discharged, while if it exceeds 5 per 1 cm ² , There is a risk that bears and the like may be generated due to insufficient rubber flow during vulcanization, but if it is within the above range, air is reliably discharged while suppressing generation of bears and the like due to insufficient rubber flow during vulcanization. Because it can.

    5 and 6 are views showing Embodiment 2 of the present invention. In this embodiment, the outer periphery of the auxiliary roller 42 is constituted by a smooth cylindrical surface, while the stitcher roll 50 is a perforated roller. Here, a large number of radially extending guide holes 51 are formed substantially uniformly on the outer periphery of the stitcher roll 50, and each guide hole 51 is located on the radially outer side and on the radially inner side. The large-diameter portion 53 is larger than the small-diameter portion 52.

  Reference numeral 54 denotes a piercing needle having the same diameter as the small diameter portion 52 and having a cylindrical shape. A flange 55 having the same diameter as the large diameter portion 53 is integrally formed at the radially inner end of the piercing needle 54. The piercing needle 54 and the flange 55 have a radius in the guide hole 51 with the piercing needle 54 slidably engaged with the small diameter portion 52 and the flange 55 slidably engaged with the large diameter portion 53. It is inserted to be movable in the direction. Further, a spring 56 is interposed between the flange 55 and the bottom surface of the large diameter portion 53 of the guide hole 51. As a result, the piercing needle 54 and the flange 55 are connected to the small diameter portion 52 by the urging force of the spring 56. To the position in contact with the step provided at the boundary between the large-diameter portion 53 and the outer diameter portion 53 to move radially outward.

  At this time, the protruding amount P of the piercing needle 54 from the outer periphery of the stitcher roll 50 to the tip end (radial outer end) of the piercing needle 54 is slightly larger than the thickness t of the rubber strip 21, and as a result, the rubber strip 21 becomes the stitcher roll. When reaching between 50 and the auxiliary roller 42, the piercing needle 54 is pushed into the rubber strip 21, and a through hole 47 similar to the above is formed in the rubber strip 21 so as to penetrate between the front and back surfaces. Here, when the pressing force of the stitcher roll 50 against the forming drum 11 exceeds the urging force of the spring 56, when the punching needle 54 reaches the winding point K, the punching force is generated by the reaction force from the forming drum 11. The needle 54 and the flange 55 are pushed inward in the radial direction while compressing the spring 56.

  As a result, the stitcher roll 50 (piercing needle 54) forms a through hole 47 in the rubber strip 21 at the position closest to the auxiliary roller 42, while the rubber strip 21 is pressed against the forming drum 11 at the winding point K. It can play two roles of crimping. Here, the flange 55 described above is used as a piston, compressed air is used instead of the spring 56, or the large diameter portion 53 is filled with hydraulic oil, and the flange 55 itself or the flange 55 and the large diameter portion are filled. A diaphragm may be provided between the large diameter portion 53 and the large diameter portion 53 and the flange 55 as a dash pot. Other configurations and operations are the same as those in the first embodiment.

    FIG. 7 is a diagram showing a third embodiment of the present invention. In this embodiment, the outer periphery of the auxiliary roller 42 is formed of a smooth cylindrical surface, while the perforation roller 61 provided with a perforation needle 60 similar to the perforation needle 45 on the outer periphery is inserted from the winding point K of the molding drum 11. It is arranged around the forming drum 11 in the forward direction of rotation. Here, the perforating roller 61 is rotatably supported at the tip of the piston rod 64 of the fluid cylinder 63 as pressing means attached to the upper movable plate 35 via a bracket (not shown). The perforating roller 61 can be rotated while being in rolling contact with the rubber strip 21 immediately after being wound around the molding drum 11.

  When the perforating roller 61 is in rolling contact with the rubber strip 21 immediately after winding as described above, the perforating needles 60 of the perforating roller 61 are pushed into the rubber strip 21 one after another and penetrate between the front and back surfaces of the rubber strip 21. A large number of through holes 47 are formed. Here, if the fluid pressure supplied to the fluid cylinder 63 is adjusted, the pressing force of the perforating roller 61 against the rubber strip 21 can be adjusted. As a result, the rubber type, thickness, etc. of the rubber strip 21 are changed. Even if there is, the through hole 47 can be reliably formed by dealing with this easily. Other configurations and operations are the same as those in the first embodiment.

    In the above-described embodiment, the auxiliary roller 42, the stitcher roll 50, and the perforation roller 61 as the perforation roller are disposed in the vicinity of the winding point K of the rubber strip 21 with respect to the forming drum 11. However, in the present invention, the perforation roller May be disposed at a position in contact with the travel path of the rubber strip 21 between the extruder 20 and the molding drum 11, or a position in contact with the rubber strip 21 wound around the molding drum 11 around the molding drum 11. , May be far away from the winding point K.

  In the above-described embodiments, the tire rubber layer is the tread 17. However, in the present invention, the tire rubber layer may be a cushion rubber, a squeegee rubber, a side tread, and the like. A two-layer structure of a cap rubber layer and a base rubber layer may be used. Further, in the above-described embodiment, the rubber strip 21 is wound around the expansion / contraction molding drum 11 to form the tire rubber layer (tread 17). In this invention, the outer surface is the inner surface of the pneumatic tire. The rubber layer for tires may be formed by winding a rubber strip around a molding drum (rigid core) having the same shape as the above.

  The present invention can be applied to the industrial field in which a rubber layer for a tire such as a tread is formed by spirally winding a rubber strip.

BRIEF DESCRIPTION OF THE DRAWINGS It is a partially broken schematic front view which shows Example 1 of this invention. FIG. It is front sectional drawing explaining the drilling operation | work with respect to a rubber strip. It is front sectional drawing explaining the other drilling operation | work with respect to a rubber strip. It is a figure which shows Example 2 of this invention, and is front sectional drawing explaining the drilling | piercing operation | work with respect to a rubber strip. It is front sectional drawing of the piercing needle vicinity. It is a figure which shows Example 3 of this invention, and is front sectional drawing explaining the drilling | piercing operation | work with respect to a rubber strip.

Explanation of symbols

11 ... Molding drum 17 ... Tire rubber layer
21… Rubber strip 42… Perforation roller
43 ... Supply means 45 ... Perforation needle
47 ... Through hole 63 ... Pressing means

Claims (7)

    A rubber for a tire in which a rubber strip made of unvulcanized rubber is supplied to a molding drum rotating around an axis, and the rubber strip for a tire is molded by spirally winding the rubber strip around the rubber strip. In the method for forming a layer, a through hole that penetrates between the front and back surfaces of the rubber strip that has been supplied or has been wound is formed by a perforating needle. The method for molding a tire rubber layer according to claim 1, wherein a cross-sectional area at a minimum cross-sectional position of the through hole is in a range of 1 to 3 mm ² . The method for forming a tire rubber layer according to claim 1 or 2, wherein only 1 to 5 through holes are formed in a rubber strip per 1 cm ² .     A tire molding drum rotatable around an axis and a rubber strip made of unvulcanized rubber are fed to the rotating molding drum while traversing, and the rubber strip is spirally wound around the outer side of the molding drum. In a tire rubber layer molding apparatus comprising a supply means for molding a rubber layer for a tire, a perforation roller that is capable of rolling contact with the rubber strip and provided with a perforation needle inserted into the rubber strip is provided on the outer periphery, An apparatus for forming a tire rubber layer, characterized in that a through-hole penetrating between the front and back surfaces of the rubber strip that has been supplied or wound is formed by a punch needle of a punch roller.     5. The tire rubber layer molding apparatus according to claim 4, wherein the punch needle has the same cross-sectional shape from the base end to the tip end on the punch roller side.     5. The tire rubber layer molding apparatus according to claim 4, wherein the perforating needle is tapered from the base end toward the front end on the perforation roller side.     The tire rubber layer forming apparatus according to any one of claims 4 to 6, further comprising a pressing unit that can press the punching roller against a rubber strip while adjusting a pressing force.

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