JP2008018620A - Method for manufacturing pneumatic tire, and pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve working efficiency by shortening switching time for a ribbon-like body 51. <P>SOLUTION: After a channel 45 in the peripheral direction is formed on the outer surface of a side body 38, as the ribbon-like body 51 consisting of a rubber with a different color from that of the side body 38 is fed in the channel 45 in the peripheral direction and is wound and laminated, before winding and laminating the ribbon-like body 51, the side body 38 is molded in a specified shape, namely, a completed shape except the channel 45 in the peripheral channel 45. As a result, the switching work when the ribbon-like body 51 with the different color is started to be wound, becomes at most one time, to improve the working efficiency. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

    The present invention relates to a method for manufacturing a pneumatic tire in which different color lines and the like are provided on a sidewall portion, and a pneumatic tire.

As a conventional method for manufacturing a pneumatic tire, for example, a method described in Patent Document 1 below is known.
JP 2005-212197 A

  When manufacturing a raw tire using a rigid core or the like whose outer surface has the same shape as the inner surface of a pneumatic tire, the side tread is formed on both outer sides in the axial direction of the carcass layer deformed into a toroidal shape. Although such a side tread is attached, the outer side of the first ribbon-like body made of rubber of the same color as that of the main body rubber, usually black, is spirally wound from the vicinity of the tread end toward the tire maximum width position. After forming the side part, a second ribbon-like body made of rubber, which is a different color from the first ribbon-like body, usually white rubber, continues to the outer side part, and is wound several times in a spiral toward the bead part. Next, again, the first ribbon-like body is continuously connected to the line portion, and the inner side portion is formed by winding a number of times in a spiral toward the bead portion.

    However, in such a conventional method for manufacturing a pneumatic tire, in order to form a side tread having a line portion, from the first ribbon-like body to the second ribbon-like body, the second ribbon-like body is subsequently formed. The supplied ribbon-like body has to be switched twice from the body to the first ribbon-like body, but switching the ribbon-like body of different colors is troublesome, so switching takes a long time. There was a problem that work efficiency would be reduced.

  An object of this invention is to provide the manufacturing method of the pneumatic tire which can improve work efficiency by shortening the switching time of a ribbon-like body.

    The purpose of this is to form a circumferential groove extending in the circumferential direction on the outer surface of the side main body made of the same color rubber of the raw tire, and a rubber of a different color from the side main body while rotating the raw tire around the central axis. A ribbon-shaped body having a constant width is supplied into the circumferential groove and laminated while being wound, and the circumferential groove is filled with the ribbon-shaped body, and the raw tire is vulcanized at high temperature and high pressure. It can achieve by providing with the process made into a pneumatic tire.

  In this invention, after forming the circumferential groove on the outer surface of the side body, the ribbon-like body is supplied into the circumferential groove and wound and laminated, so prior to the winding and lamination of the ribbon-like body. The side main body is formed in a predetermined shape. As a result, the switching operation at the start of winding of the ribbon-like bodies having different colors is performed once or less, thereby improving the work efficiency.

  Here, when the ribbon-like body is wound and laminated while being inclined with respect to the outer surface of the side main body, when it becomes a pneumatic tire, minute unevenness is generated by the opening side end edge portion of the ribbon-like body. As a result, the appearance deteriorates and distortion may concentrate when the side wall portion is deformed. If configured as described in claim 2, the final wound ribbon-like body located at the opening of the circumferential groove Since the surface is flat and substantially parallel to the outer surface of the side body, the appearance is improved and the concentration of distortion can be effectively suppressed.

  Moreover, if comprised as described in Claim 3, it can respond to the groove width change in the depth direction of a circumferential direction groove | channel with a single kind of ribbon-shaped body, For many types of extruders from which extrusion width differs There is no need to prepare a base. Furthermore, if comprised as described in Claim 4, the tension | tensile_strength provided to a ribbon-like body can be adjusted easily and with high precision. Further, if the tension change position is the same position in the circumferential direction, the change in thickness is accumulated at the same position and a step is generated. Occurrence can be suppressed.

  Furthermore, if comprised as described in Claim 6, the air entering between the side surface of a circumferential groove | channel and the width direction both sides | surfaces of a ribbon-shaped body can be suppressed effectively. In addition, when the ribbon-like body is supplied to the circumferential groove while being parallel to the outer surface of the side body, the ribbon-like body is greatly stretched in the longitudinal direction toward the side closer to the top tread, and the thickness is reduced. If it comprises as described in (1), thickness will become substantially uniform after winding lamination | stacking, and the circumferential direction groove | channel can be filled with a ribbon-shaped body uniformly.

Embodiment 1 of the present invention will be described below with reference to the drawings.
In FIGS. 1 and 2, reference numeral 11 denotes a fixed frame, and a horizontal rotary shaft 13 is rotatably supported by the fixed frame 11 via a bearing 12 fixed to the fixed frame 11. 14 is a metal rigid core coaxial with the rotary shaft 13 which is detachably attached to one end of the rotary shaft 13, and the rigid core 14 has a donut shape as a whole and has an outer surface in the radially outer portion. Has a core body 15 having the same shape as the inner surface of the vulcanized pneumatic tire. The core body 15 includes a plurality of fan-shaped segments and a plurality of chevron segments alternately arranged in the circumferential direction with the fan-shaped segments.

  Reference numeral 17 denotes a one-side ring body that is locked to one side of the inner end of the core body 15 in the radial direction. A male thread 18 is formed on the outer periphery of the other end of the one-side ring body 17. . Reference numeral 19 denotes an other-side ring body that is locked to the other end at the radially inner end of the core body 15, and an internal thread portion 20 is formed on the inner periphery of the other-side ring body 19. The fan-shaped segment and the chevron-shaped segment constituting the core body 15 are connected to each other by the one-side ring body 17 and the other-side ring body 19 that are connected to each other by screwing the female thread section 20 to the male thread section 18. It is clamped and fastened firmly.

  23 is a pulley fixed to the other end of the rotary shaft 13, and a timing belt 27 is stretched between the pulley 23 and a pulley 26 fixed to the output shaft 25 of the drive motor 24. When the drive motor 24 operates and the output shaft 25 rotates, the rotation of the output shaft 25 is transmitted to the rotary shaft 13 via the pulley 26, the timing belt 27, and the pulley 23, and the rotary shaft 13 and the rigid core 14 Are integrally rotated around the rotation axis 13 and the central axis of the rigid core 14. Reference numeral 28 denotes an encoder that detects the rotation of the drive motor 24.

  31 is a green tire covering the radially outer portion of the rigid core 14 from the outside. The green tire 31 is formed as follows, for example. First, while rotating the rotating shaft 13 and the rigid core 14 by the drive motor 24, a rubber ribbon is supplied around the rigid core 14 and wound many times in a spiral shape and a spiral shape to form the inner liner 32. Next, an inner bead layer 33 is formed by winding a bead wire made of single wire steel coated with rubber on the outside of the inner liner 32 in the bead part B in a spiral shape a plurality of times.

  Next, while rotating the rigid core 14, a carcass wire made of rubber-coated steel cord or single wire steel is supplied around the rigid core 14 (inner liner 32), and both beads are folded back at both bead portions B. The carcass layer 34 is formed by extending the portion B in the meridian direction. Thereafter, the outer bead layer 35 is formed by winding a bead wire made of single wire steel coated with rubber on the outer side of the carcass layer 34 in the bead part B in a spiral shape. As a result, the carcass layer 34 is sandwiched from both sides by the bead layer 36 constituted by the inner bead layer 33 and the outer bead layer 35, and is strongly moored.

  Next, a rubber ribbon is wound in a spiral manner on the outer side in the axial direction of the carcass layer 34 in the side wall portion S, and the side main body 38 is wound on the outer side in the axial direction of the rigid core 14 and the bead layer 36 in the bead portion B. The rubber chafer 39 is formed by winding a large number of times in a spiral shape. Further, after forming a plurality of belt layers 40 by spirally winding a ribbon-like body formed by coating several cords with rubber on the outer side in the radial direction of the carcass layer 34 in the tread portion T. The top tread 41 is formed by winding a rubber ribbon many times around the belt layer 40 in the radial direction.

  Here, the side main body 38, the rubber chafer 39, and the top tread 41 described above are made of rubber having physical properties corresponding to the portions provided, but these are made of rubber of the same color, usually black. The side body 38 is formed by sticking a rubber sheet having a full width at the start and end of one rubber sheet extruded from an extruder, and sticking it to the outside of the carcass layer 34 in the axial direction. May be.

  1, 2, 3, and 4, a circumferential groove 45 that extends continuously in the circumferential direction is formed on the outer surface of the side body 38 on one side in the axial direction when the side body 38 is molded with the rubber ribbon as described above. However, the circumferential groove 45 is composed of a bottom surface 46 extending substantially parallel to the outer surface of the side body 38 and two side surfaces 47 inclined in opposite directions at substantially the same angle with respect to the outer surface of the side body 38. ing. As a result, the circumferential groove 45 gradually becomes wider from the bottom surface 46 toward the opening 48, and the overall cross-sectional shape is a trapezoid.

  51 is a ribbon-shaped body made of rubber, which is different in color from the side body 38 used for decoration, usually white rubber, and this ribbon-shaped body 51 is formed on the raw tire 31, more specifically on the side body 38 as described above. Into the circumferential groove 45 formed. The ribbon-like body 51 described above is supplied to the circumferential groove 45, for example, immediately after being extruded from the extruder or after being once wound up in a roll shape and being unwound from the roll. The

  Here, the ribbon-like body 51 is supplied into the circumferential groove 45 in such a posture that the front and back surfaces thereof are parallel to the outer surface of the side body 38. At this time, the ribbon-like body 51 is provided with a pressing roller 52. Is pressed toward the bottom surface 46 of the circumferential groove 45, and thus the circumferential groove 45 is laminated while being spirally wound from the bottom surface 46 toward the opening 48 in the circumferential groove 45. Filled with.

  In this way, while rotating the green tire 31 around the central axis, the ribbon-like body 51 made of rubber of a color different from that of the side main body 38 is supplied into the circumferential groove 45 and laminated while being wound, and the ribbon-like body 51 When the entire space of the circumferential groove 45 is filled, the ribbon-like body 51 filling the circumferential groove 45 becomes a ring-like embedded rubber 53 as a whole, and the embedded rubber 53 and the side main body 38 are formed as a side tread 54 as a whole. Configure.

  Here, the ribbon-like body 51 may be wound and laminated while being inclined with respect to the outer surface of the side main body 38 as in Embodiment 2 described later. As shown in FIG. 5, minute irregularities are generated by the opening 48 side end edge portion 55 of the ribbon-like body 51. As a result, the appearance is deteriorated, and distortion may be concentrated when the sidewall portion S is deformed. .

  However, as in this embodiment, the ribbon-like body 51 is supplied to the circumferential groove 45 in a posture in which the front and back surfaces are parallel to the outer surface of the side body 38, and the ribbon-like body 51 is supplied to the bottom surface 46 of the circumferential groove 45. If the layers are stacked while being spirally wound from the opening 48 toward the opening 48, the surface of the final ribbon-like body 51 located at the opening 48 of the circumferential groove 45 is flat, and the outer surface of the side body 38 Therefore, the appearance can be improved and the concentration of distortion can be effectively suppressed.

  Further, in this embodiment, the width of the ribbon-like body 51 is increased toward the opening 48 of the circumferential groove 45, that is, the width of the ribbon-like body 51 is increased toward the surface of the ribbon-like body 51. The inclination of the surface is approximated to the inclination of the side surface 47 of the circumferential groove 45, and here it is matched. As a result, when the ribbon-shaped body 51 is wound and laminated in the circumferential groove 45, a situation in which a gap is generated between the side surface 47 of the circumferential groove 45 and both side surfaces in the width direction of the ribbon-shaped body 51 is suppressed. Air entering between these can be effectively suppressed.

  Further, it is preferable that the ribbon-like body 51 supplied to the circumferential groove 45 has a thickness that increases as it approaches the top tread 41. The reason for this is that when the ribbon-like body 51 is supplied to the circumferential groove 45 while being parallel to the outer surface of the side main body 38 and wound and laminated, the ribbon-like body 51 is stretched in the longitudinal direction to the side closer to the top tread 41. This is because, as described above, the thickness becomes substantially uniform after winding and lamination, and the circumferential groove 45 can be uniformly filled with the ribbon-like body 51.

  57 is a tension roller installed on the upstream side of the pressing roller 52 on the travel path of the ribbon-like body 51, and the ribbon-like body 51 in the middle of supply to the pressing roller 52 is not shown in the drawing. It is pressed by a roller. The tension roller 57 is fixed to an output shaft 59 of a drive motor 58, and an encoder 60 for detecting the rotation of the drive motor 58 is attached to the drive motor 58. 61 is a control means connected to the drive motor 58, encoder 60, drive motor 24, and encoder 28. This control means 61 outputs a control signal to the drive motors 58, 24 to rotate the drive motors 58, 24. In addition to the control, the drive motors 58 and 24 are feedback-controlled based on detection signals from the encoders 60 and 28.

  Here, since the width of the circumferential groove 45 gradually increases from the bottom surface 46 toward the opening 48 as described above, as the winding of the ribbon-like body 51 approaches from the start to the end, the ribbon-like body 51 Following this, the width of must be gradually widened. For this reason, in this embodiment, the control means 61 controls the operation of the drive motors 24, 58. Here, the rotation speed of the drive motor 24 is kept constant, while at the start of winding, the drive motor 58 By reducing the rotation speed of the ribbon-like body, the supply speed of the ribbon-like body 51 from the tension roller 57 to the circumferential groove 45 is made lower than the circumferential speed (winding speed) at the winding point of the ribbon-like body 51. A large longitudinal tension is applied to the body 51, whereby the ribbon-like body 51 is greatly stretched in the longitudinal direction so that the width of the ribbon-like body 51 matches the narrow width at the bottom of the circumferential groove 45.

  As the winding of the ribbon-like body 51 in the circumferential groove 45 proceeds, the number of windings of the ribbon-like body 51 increases, and the width of the circumferential groove 45 at the position where the ribbon-like body 51 is wound is increased. However, at this time, the rotational speed of the drive motor 58 is gradually increased for each rotation of the raw tire 31, and the supply speed of the ribbon-shaped body 51 is brought close to the peripheral speed at the winding point. The tension applied to is gradually reduced, thereby gradually increasing the width of the ribbon 51 and returning it to its original width (a constant width equal to or greater than the width at the opening 48 of the circumferential groove 45). . Thus, if the tension applied to the ribbon-like body 51 is adjusted by controlling the supply speed of the ribbon-like body 51 and the peripheral speed (winding speed) at the winding point of the ribbon-like body 51, The tension applied to the ribbon-like body 51 can be adjusted easily and with high accuracy.

  Further, as described above, if the tension applied to the ribbon-like body 51 being supplied is reduced as the winding progresses, the ribbon-like body 51 of a single type (a constant width upstream from the tension roller 57) can be obtained. It is possible to cope with a change in the groove width in the depth direction of the circumferential groove 45, and it is not necessary to prepare various types of extruder caps, and it is possible to reduce storage space and improve work efficiency.

  As described above, when the tension applied to the ribbon-like body 51 is reduced (changed), it is preferable to disperse the tension change position to some extent in the circumferential direction. The reason for this is that the ribbon-like body 51 changes not only in width but also in thickness as the tension changes. If the tension change position is the same in the circumferential direction, the same position in the circumferential direction where the thickness change changes. This is because the steps are accumulated and the steps are generated as described above.

  Here, while the rotation speed of the tension roller 57 (the supply speed of the ribbon-like body 51) is made constant, the rotation speed of the rigid core 14 and the raw tire 31 (the peripheral speed at the winding point of the ribbon-like body 51) is controlled. Thus, the tension applied to the ribbon-like body 51 may be adjusted, or the rotational speed of the tension roller 57 (the supply speed of the ribbon-like body 51) and the rotational speed of the rigid core 14 and the raw tire 31 ( The tension applied to the ribbon-like body 51 may be adjusted by controlling both of the circumferential speed at the winding point of the ribbon-like body 51.

  On the other hand, the pressing roller 52 has a pair of central rollers 66 fixed to the support shaft 65 and a pair of outer rollers 67 splined to the support shaft 65 on the axially outer side of the central rollers 66. Between the central roller 66 and the outer roller 67, a spring 68 that biases the outer roller 67 outward in the axial direction is interposed. Here, the support shaft 65 extends in parallel to the radial direction of the raw tire 31 and is rotatably supported by the moving frame 64. The moving frame 64 receives a moving force from a moving mechanism (not shown). The rotary shaft 13 can move in the axial direction.

  As a result, as shown in FIG. 4, when the pressing roller 52 presses the ribbon-like body 51 in the middle of winding in the circumferential groove 45, the outer roller 67 moves from the side surface 47 of the circumferential groove 45 to the central roller. In response to the pressing force in the direction approaching 66, it moves inward in the axial direction, and the distance between the outer ends in the axial direction of these outer rollers 67 has the same value as the width of the ribbon-like body 51 at the winding point.

  Thereafter, as the number of layers of the ribbon-like body 51 wound in the circumferential groove 45 gradually increases, the outer roller 67 is correspondingly separated from the central roller 66 by the biasing force of the spring 68 in the axial direction. Move outward. When the winding and laminating of the ribbon-like body 51 in the circumferential groove 45 is finished, the pressing roller 52 comes out of the circumferential groove 45. At this time, the outer roller 67 is moved to the stoppers 69 provided at both ends of the support shaft 65. It abuts and is prevented from coming out of the support shaft 65.

  If the axial length of the entire pressing roller 52 is increased as the width of the ribbon-like body 51 wound in this way is increased, the degree of adhesion of the ribbon-like body 51 in each layer is improved over the entire area. Entering and the like can be effectively suppressed. Note that the start and end of the ribbon-like body 51 when wound until the circumferential groove 45 is completely filled are the same circumferential position in order to prevent the thickness of the embedded rubber 53 from changing in the circumferential direction. And However, steps are likely to be formed at the start and end positions. Therefore, when forming a character or the like that intersects the circumferential groove 45 with rubber of the same color as the ribbon 51 on the outer surface of the raw tire 31, The start and end positions are preferably separated from the position.

  After forming the circumferential groove 45 on the outer surface of the side body 38 in this way, the ribbon-like body 51 is supplied into the circumferential groove 45 and wound and laminated. Prior to lamination, the side main body 38 is formed into a predetermined shape, that is, only the portion of the circumferential groove 45 is recessed, but the other is a completed shape. The switching operation of the ribbon-shaped body 51 at the start of winding is only once or less, and here, only one switching from the rubber ribbon forming the side main body 38 to the ribbon-shaped body 51 is performed, and the work efficiency is improved. When the side main body 38 is formed by joining the start and end of the rubber sheet, the switching operation is not necessary.

  When the raw tire 31 including the side tread 54 is formed in such a manner that the circumferential groove 45 is filled with the ribbon-like body 51 in this way, after removing the rigid core 14 to which the raw tire 31 is attached from the rotating shaft 13, It is carried directly into the vulcanizer. Thereafter, a vulcanizing medium is supplied into the vulcanizing device and the rigid core 14, the raw tire 31 is vulcanized under high temperature and high pressure, and the side wall portion S is provided with a different color, for example, a white line. Manufacture tires.

    FIG. 5 is a diagram showing Embodiment 2 of the present invention. In this embodiment, the ribbon-like body 51 is spirally wound and laminated in the circumferential groove 45 in a posture parallel to the side face 47 located on the radially inner side. In this case, since the ribbon-like body 51 is inclined with respect to the outer surface of the side body 38, when the ribbon-like body 51 is made of rubber that does not flow easily during vulcanization, the opening of the ribbon-like body 51 Although there is a possibility that minute irregularities may be generated on the surface of the embedded rubber 53 by the 48 side end edge portion 55, it can be used without any problem when it is made of a rubber that easily flows. Further, the supply of the ribbon-like body 51 into the circumferential groove 45 is easier than in the first embodiment, and the workability is also good.

    In the above-described embodiment, the raw tire 31 is molded using the rigid core 14. However, in the present invention, the core body provided in the central portion in the axial direction during the molding of the raw tire 31 is expanded. The raw tire 31 may be molded using a molding drum having a diameter, and further, the raw tire 31 may be molded using a normal tire molding drum that is deformed into a substantially toroidal shape by filling with internal pressure. In the above-described embodiment, the circumferential groove 45 is a groove that is continuous in the circumferential direction. However, in this invention, the circumferential groove is an arc-shaped groove that does not make one round in the circumferential direction and ends in the middle. There may be.

  Furthermore, in the above-described embodiment, the tension applied to the ribbon-like body 51 is adjusted by controlling the supply speed of the ribbon-like body 51 and the peripheral speed at the winding point of the ribbon-like body 51. However, in the present invention, two rollers are provided on the travel path of the ribbon-like body 51 on the upstream side of the pressing roller 52, and the rotational speed of these two rollers is controlled, so that a ribbon-like shape is formed between these rollers. The tension (width) of the body 51 may be adjusted. Further, the outer side of the embedded rubber 53 may be covered with a coating rubber of the same color as that of the side main body 38, and after vulcanization, the coated rubber may be removed by grinding to expose the embedded rubber 53.

  Furthermore, in the above-described embodiment, the width of the circumferential groove 45 is continuously increased from the bottom surface 46 toward the opening 48. However, in the present invention, the width may be increased stepwise. In this case, the longitudinal tension applied to the ribbon-like body 51 is also made small stepwise following the change in the width. In the present invention, the width of the circumferential groove 45 may be constant from the bottom surface 46 toward the opening 48. In this case, it is not necessary to control the width of the ribbon-like body 51 at the time of supply.

  The present invention can be applied to the industrial field of manufacturing pneumatic tires.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic front view with a part broken away showing Embodiment 1 of the present invention. It is front sectional drawing of the side tread vicinity. FIG. 3 is a cross-sectional view taken along a line II in FIG. 2. It is II-II arrow sectional drawing of FIG. It is sectional drawing similar to FIG. 4 which shows Embodiment 2 of this invention.

Explanation of symbols

31 ... Raw tire 38 ... Side body
41 ... Top tread 45 ... Circumferential groove
46… Bottom 47… Side
48 ... Opening 51 ... Ribbon

Claims (8)

    A step of forming a circumferential groove extending in the circumferential direction on the outer surface of the side main body made of the same color rubber of the raw tire, and a ribbon-like body made of rubber of a color different from that of the side main body while rotating the raw tire around the central axis Supplying into the circumferential groove and laminating while winding, filling the circumferential groove with the ribbon-like body, and vulcanizing the raw tire at high temperature and high pressure to form a pneumatic tire A method for producing a pneumatic tire, characterized in that     The ribbon-like body is supplied to the circumferential groove in a posture in which the front and back surfaces are parallel to the outer surface of the side body, and the ribbon-like body is laminated while being spirally wound from the bottom surface of the circumferential groove to the opening. The manufacturing method of the pneumatic tire of Claim 1 which was made to do.     The pneumatic according to claim 1 or 2, wherein when the circumferential groove is wide from the bottom surface toward the opening, the longitudinal tension applied to the ribbon-like body being supplied is reduced as the winding progresses. Tire manufacturing method.     The method for manufacturing a pneumatic tire according to claim 3, wherein the tension applied to the ribbon-like body is adjusted by controlling a supply speed of the ribbon-like body and a peripheral speed at a winding point of the ribbon-like body. .     The method for manufacturing a pneumatic tire according to claim 3 or 4, wherein the change positions of the tension are dispersed in the circumferential direction.     The width of the ribbon-shaped body is increased as it goes toward the opening of the circumferential groove, and the inclination of both side surfaces in the width direction of the ribbon-shaped body is approximated to the inclination of the side surface of the circumferential groove. Method of manufacturing a pneumatic tire.     The method for manufacturing a pneumatic tire according to claim 2, wherein the ribbon-like body supplied to the circumferential groove is thicker as its thickness approaches the top tread.     A pneumatic tire manufactured using the manufacturing method according to claim 1.

Images