JP2017109443A - Method for producing green tire and method for producing pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a green tire and a method for producing a pneumatic tire which can reduce mass imbalance.SOLUTION: The methods include a molding step for molding an unvulcanized green tire 1, a measurement step for measuring the mass imbalance of the molded green tire 1, and a sticking step for sticking an unvulcanized rubber member to a position at which the mass imbalance measured in the measurement step can be reduced.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a green tire and a method for manufacturing a pneumatic tire.

  In general, when manufacturing a pneumatic tire, a cylindrical belt tread assembly is formed by sequentially attaching a plurality of belt plies and tread rubber on a forming drum, while an inner liner, carcass is formed on another forming drum. A cylindrical green tire body is formed by laminating beads, sidewall rubber, and the like. And, by causing the green tire body to bulge in a toroidal shape with a shaping drum, the outer peripheral surface of the green tire body is pressure-bonded to the inner peripheral surface of the belt tread assembly that has been standby in advance in the radially outward direction. Mold green tires. The obtained green tire is set in a vulcanization molding die, and vulcanization molding is performed in a state where a tread rubber is pressed against the inner surface of the molding die to obtain a pneumatic tire.

  Tire components such as belt plies, inner liners, and carcass that make up green tires are made up of a belt-shaped rubber member that is wound around the periphery of a molding drum and the ends thereof are stacked and joined together. There are many joints between members. The joints of the tire constituent members cause mass imbalance in the tire circumferential direction. Therefore, for members such as carcass and tread rubber that greatly affect mass unbalance, the mass unbalance may be suppressed by dispersing the joints of these members in the tire circumferential direction.

  However, there are many reinforcing layer joints such as bead fillers and inner liners as joints of the tire constituent members constituting the pneumatic tire, and the joints of the constituent members are dispersed in the tire circumferential direction as described above. Since there are a large number of mass imbalance elements that cannot be compensated even if it is applied, there is a possibility that the mass imbalance in the tire circumferential direction cannot be sufficiently reduced by such a method.

  In Patent Documents 1 and 2, a dimensional non-uniformity in the tire radial direction called RRO (Radial Run Out) is measured for the molded green tire, and the tread rubber indicates that the measurement result is outside the allowable range. A method of manufacturing a green tire has been proposed in which RRO is corrected by cutting or pressing the tire. However, in these documents, the outer shape of the molded green tire can be made uniform, but the mass imbalance is not corrected.

JP-A-2005-47154 JP 2001-212888 A

  An object of this invention is to provide the manufacturing method of the green tire which can reduce mass imbalance, and the manufacturing method of a pneumatic tire in view of the above point.

  The green tire manufacturing method according to the present invention includes a molding step of molding an unvulcanized green tire, a measurement step of measuring a mass imbalance of the molded green tire, and a mass ratio measured in the measurement step. And a pasting step of pasting an unvulcanized rubber member at a position where the balance is reduced.

  Further, the method for manufacturing a pneumatic tire according to the present invention is measured by a molding step of molding an unvulcanized green tire, a measurement step of measuring mass unbalance of the molded green tire, and the measurement step. This includes a pasting step of pasting an unvulcanized rubber member at a position where the mass unbalance is reduced, and a vulcanizing step of vulcanizing and molding the obtained green tire.

  According to the present invention, the mass unbalance of the molded green tire is measured, and the unvulcanized rubber member is attached to the position where the mass unbalance of the green tire is reduced based on the measurement result. A green tire and a pneumatic tire with reduced mass unbalance can be obtained without considering the arrangement of joints of the constituent members.

It is a flowchart which shows the manufacturing method of the pneumatic tire which concerns on this embodiment. It is a cross-sectional schematic diagram which shows a green tire. It is a cross-sectional schematic diagram which shows a shaping drum. It is a cross-sectional schematic diagram which shows a balancer apparatus.

  Embodiments of the present invention will be described below with reference to the drawings. The present embodiment is a method for producing a pneumatic tire by producing an unvulcanized green tire and vulcanizing the produced green tire. As shown in FIG. 1, the manufacturing method of the present embodiment includes a green tire forming step, a measuring step, a pasting step, a re-measuring step, a correcting step, and a vulcanizing step. Hereinafter, each process until a pneumatic tire is obtained will be described.

(1) Green tire molding process (step S1)
As shown in FIG. 2, the green tire 1 includes a toroidal green tire body 2 and a belt tread assembly 10 that is pressure-bonded to the outer peripheral surface thereof.

  The green tire body 2 is a primary molding machine in which a carcass layer 4 is attached to the outer peripheral surface of the inner liner 3 and a pair of beads 5 and 6 including bead cores 5A and 6A and bead fillers 5B and 6B are attached to both ends of the carcass layer 4. Are arranged so that both ends of the carcass layer 4 wrap around the beads 5 and 6, and side wall rubbers 7 and 8 are attached to form a cylindrical member, which is swelled in a toroidal shape by the shaping drum 20. It is formed by letting out.

  As shown in FIG. 3, the shaping drum 20 includes a main shaft 21 that is supported in a cantilever manner by the drive unit, and a pair of bead holding members 22 and 23 provided on the main shaft 21.

  One end of an air supply hole 21a provided in the axial direction of the main shaft 21 opens in the middle of the two bead holding members 22 and 23, and the other end opens in the end face on the drive unit side. It is connected to the air compressor via a supply pipe.

  Further, at least one of the bead holding members 22 and 23 is provided so as to be slidable in the axial direction of the main shaft 21, and the interval between the bead holding members 22 and 23 can be changed in the axial direction of the main shaft 21. Yes. Locking grooves 22 a and 23 a for locking the beads 5 of the green tire main body 2 are recessed in the outer periphery of the bead holding members 22 and 23.

  When the beads 5 and 6 of the cylindrical member formed by the primary molding machine are attached to the locking grooves 22a and 23a of the bead holding members 22 and 23, the shaping drum 20 has a gap between the bead holding members 22 and 23. Air supply hole until a predetermined internal pressure is reached inside the green tire body 2 (inner peripheral side of the inner liner 3) held by the bead holding members 22 and 23 while being narrowed to a predetermined interval (rim width) R set in advance. Pressurized air is supplied from 21a. Thus, the green tire body 2 is deformed into a toroidal shape with a predetermined internal pressure filled inside while the pair of beads 5 and 6 are held at a predetermined rim width R.

  The belt tread assembly 10 is a cylindrical member formed by winding a belt 12 and a tread rubber 14 around an outer peripheral surface of a molding drum (not shown), and the inner peripheral surface thereof is the carcass layer 4 of the green tire body 2. Crimped and integrated with the outer peripheral surface. The belt 12 includes a plurality of belt plies in which metal cords are disposed at an angle of, for example, 10 to 40 ° with respect to the tire circumferential direction. In this example, the belt 12 is configured by superposing two belt plies 12A and 12B using a steel cord as a reinforcing material. Note that a belt reinforcing layer may be formed on the outer periphery of the belt 12 before the tread rubber 14 is wound. The belt reinforcing layer can be formed by, for example, winding a long rubber-coated reinforcing cord spirally along the circumferential direction.

  Then, after attaching the green tire body 2 to the shaping drum 20 and waiting the belt tread assembly 10 on the outer side in the tire radial direction, the shaping drum 20 sets the distance between the pair of beads 5 and 6 to a predetermined rim width R. The green tire body 2 is filled with a predetermined internal pressure so that the green tire body 2 is deformed into a toroidal shape and integrated with the belt tread assembly 10 that is kept on the outside in the tire radial direction. Mold.

(2) Measurement process (step S2)
The green tire 1 molded in the molding process is measured for mass imbalance by a balancer device 40 as shown in FIG.

  Specifically, the balancer device 40 is rotatably supported by the balancer main body 42 and rotated by receiving a driving force from the drive device 45, and the rotary shaft 44 is provided with a space in the vertical direction. A pair of upper and lower rims 46 and 48 and upper and lower load sensors (load cells) 50 and 52 for detecting a force acting from the balancer body 42 that supports the rotating shaft 44 are provided. The rotation shaft 44 is provided with an air supply hole 54 along the axial direction. The air supply hole 54 has an upper end opened between a pair of upper and lower rims 46 and 48, and a lower end connected to an air supply source (not shown) such as an air compressor.

  In such a balancer device 40, first, the beads 5 and 6 of the green tire 1 to be measured are mounted on the pair of upper and lower rims 46 and 48, so that the rotation axis direction of the green tire 1 is directed upward and downward. Hold. At that time, the distance (rim width) between the pair of upper and lower rims 46 and 48 is set to the same distance as the rim width R of the bead holding members 22 and 23 set when the green tire 1 is formed in the shaping drum 20.

  When the green tire 1 is mounted on the rims 46 and 48, pressurized air is supplied from the air supply source to the inside of the green tire 1 mounted on the rims 46 and 48 through the air supply hole 54. At that time, the pressure of the pressurized air filled inside the green tire 1 is set to the same pressure as the pressurized air filled when the green tire 1 is molded in the shaping drum 20.

  Then, the balancer device 40 rotates the rotating shaft 44 in a state where the green tire 1 is mounted on the pair of rims 46 and 48, and the upper dynamic unbalance amount Wdu1 on the upper side of the green tire 1 (one rim 46 side). The upper light spot position (angle) Pdu1 in the tire circumferential direction, the lower dynamic unbalance amount Wdu2 on the lower side (the other rim 48 side) of the green tire 1, and the lower light spot position in the tire circumferential direction ( Angle) Pdu2 is measured.

  If the upper dynamic unbalance amount Wdu1 and the upper light spot position Pdu1, and the lower dynamic unbalance amount Wdu2 and the lower light spot position Pdu2 measured in the measurement process are equal to or less than a predetermined threshold value, affixing is performed. The process proceeds to the vulcanization process described later without executing the process, and if larger than the predetermined threshold value, the process proceeds to the correction process (step S3).

(3) Pasting process (step S4)
In the pasting process, the upper light spot position Pdu1 and the lower light spot position Pdu2 obtained in the above measurement process are not added with mass to cancel the upper dynamic unbalance amount Wdu1 and the lower dynamic unbalance amount Wdub2. Adhere the sulfur rubber member. The position where the unvulcanized rubber member is affixed may be the outer peripheral surface of the green tire 1 or the inner peripheral surface of the green tire 1 as long as it is a light spot position in the tire circumferential direction.

  Further, the shape of the rubber member to be attached in the attaching step is not particularly limited. For example, the rubber member may be provided in an elongated strip shape. In that case, a long and slender belt-shaped rubber member is wound once in the circumferential direction of the green tire 1, and the upper rubber point is overlapped so that a seam can be formed at the upper light spot position Pdu1 and the lower light spot position Pdu2. It is also possible to stick more rubber members to the light spot position Pdu1 and the lower light spot position Pdu2 than the other positions to cancel the upper dynamic unbalance amount Wdu1 and the lower dynamic unbalance amount Wdu2.

(4) Re-measurement process (step S5)
In the re-measurement step, the green tire 1 to which the rubber member is pasted in the pasting step, using the balancer device 40 under the same conditions as the measurement step, the upper dynamic unbalance amount Wdu1 and the upper light spot position Pdu1, The lower dynamic unbalance amount Wdu2 and the lower light spot position Pdu2 are measured.

  If the upper dynamic unbalance amount Wdu1 and the upper light spot position Pdu1, and the lower dynamic unbalance amount Wdu2 and the lower light spot position Pdu2 measured in the re-measurement step are equal to or less than a predetermined threshold value. The process proceeds to the vulcanization process, and if larger than the predetermined threshold value, the process proceeds to the correction process (step S6).

(5) Correction process (step S7)
In the correction process, the upper light spot position Pdu1 and the lower light spot position Pdu2 measured in the above remeasurement process are not subjected to mass addition to cancel the upper dynamic unbalance amount Wdu1 and the lower dynamic unbalance amount Wdub2. Adhere the sulfur rubber member. At that time, the rubber member may be pasted while leaving the rubber member pasted on the green tire 1 in the pasting step, and the rubber member pasted in the pasting step is peeled off and then the rubber member is pasted. Even more.

  When the rubber member is pasted in the correction process, the process returns to the re-measurement step (step S5), and the upper dynamic unbalance amount Wdu1 and the upper light spot position Pdub1 of the green tire 1 on which the rubber member is pasted in the correction process. The lower dynamic unbalance amount Wdu2 and the lower light spot position Pdu2 are measured by the balancer device 40, and the correction process and the re-measurement process are repeated until a predetermined threshold value or less is reached. When it reaches, the process proceeds to the vulcanization process.

(6) Vulcanization molding process (step S8)
In the vulcanization molding step, the green tire whose measurement result by the balancer device 40 has reached a predetermined threshold value or less is vulcanized. A known method can be applied to the vulcanization molding, that is, the green tire is set in a vulcanization mold according to a conventional method, and vulcanization molding is performed at 140 to 180 ° C., for example. An inset tire is obtained.

  In the present embodiment configured as described above, the mass unbalance of the molded green tire is measured, and the unvulcanized green tire is positioned at a position where the mass unbalance is reduced with respect to the unvulcanized green tire based on the measurement result. Since the rubber member is affixed, a green tire and a pneumatic tire with reduced mass unbalance can be obtained without considering the arrangement of joints of the constituent members of the green tire.

  Further, in the present embodiment, the bead holding members 22 and 23 set when the green tire 1 is molded in the shaping drum 20 are set so that the distance between the pair of upper and lower rims 46 and 48 of the balancer device 40 in the measurement process and the remeasurement process. The pressure of the pressurized air filled inside the green tire 1 is set to the same pressure as the pressurized air filled when the green tire 1 is molded in the shaping drum 20. Has been. Therefore, the deformation of the green tire 1 that occurs during the measurement of the mass unbalance can be minimized, and the mass unbalance can be accurately measured.

  Moreover, in this embodiment, in order to adjust mass imbalance by affixing an unvulcanized rubber member to the unvulcanized green tire 1, the rubber member once affixed is peeled off or another rubber member is affixed. The mass balance can be readjusted easily.

  In the attaching step and the correcting step of the present embodiment, the rubber member is wound so that an elongated belt-like rubber member is wound once in the circumferential direction of the green tire 1 and a joint is formed between the upper light point position Pdu1 and the lower light point position Pdub2. By overlapping the members, the rubber member can be reliably attached to the green tire 1 without inadvertent peeling.

  Moreover, mass imbalance can be reduced without changing the external shape of the green tire 1 by sticking a rubber member on the inner peripheral surface of the green tire 1 in the attaching step and the correcting step of the present embodiment.

  In this embodiment, the dynamic unbalance of the upper and lower surfaces is measured as the mass unbalance of the green tire 1 in the measurement process and the re-measurement process, and is not added to the position where the dynamic unbalance is reduced in the pasting process and the re-correction process. Although the case where the sulfur rubber member is attached has been described, in addition to the dynamic unbalance, the static unbalance (the static unbalance amount Wsub and the tire according to the radial distance of the green tire 1 in a state where the green tire 1 is stationary) You may measure the position Psub of the light point position in the circumferential direction.

  In such a case, from the measurement results of dynamic unbalance and static unbalance, even unbalance (couple unbalance), that is, the upper even unbalance amount Wcop1 of the green tire 1 and the upper light spot position Pcop1 and the lower The dynamic unbalance amount Wcop2 and the lower light point position Pcop2 are calculated. Then, an unvulcanized rubber member having a mass that cancels the static unbalance amount Wsub is attached to the measured light spot position Psub, and the upper light spot position Pcop1 and the lower light spot position Pcop2 are An unvulcanized rubber member having a mass that cancels the even unbalance amount Wcop1 and the lower even unbalance amount Wcop2 may be attached.

  Although some embodiments have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention.

DESCRIPTION OF SYMBOLS 1 ... Green tire, 2 ... Green tire main body, 3 ... Inner liner, 4 ... Carcass layer, 5 ... Bead, 6 ... Bead, 10 ... Belt tread assembly, 12 ... Belt, 14 ... Tread rubber, 20 ... Shaping drum, 21a ... air supply hole, 22 ... bead holding member, 22a ... locking groove, 40 ... balancer device, 42 ... balancer body, 44 ... rotating shaft, 45 ... drive device, 46 ... rim, 48 ... rim, 54 ... air supply Hole

Claims (7)

  A molding process for molding an unvulcanized green tire, a measurement process for measuring the mass unbalance of the molded green tire, and an unvulcanized rubber at a position where the mass unbalance measured in the measurement process is reduced A manufacturing method of a green tire including a pasting step of pasting a member.   2. The green tire manufacturing method according to claim 1, wherein the measuring step is performed while holding the green tire at a rim width when the green tire is molded in the molding step.   The method for manufacturing a green tire according to claim 1 or 2, wherein the measuring step is performed while holding the green tire at an internal pressure when the green tire is formed in the forming step.   The said sticking process winds the said rubber member in the circumferential direction of a green tire, The said rubber member is piled up in the position which reduces the mass imbalance measured at the said measurement process. Green tire manufacturing method.   The remeasurement step of measuring the mass unbalance of the green tire after the attaching step and the correcting step of attaching the rubber member to a position that reduces the mass imbalance measured in the remeasurement step. 5. The method for producing a green tire according to any one of 4 above.   The manufacturing method of the green tire of any one of Claims 1-5 which affix the said rubber member on the internal peripheral surface of the said green tire.   A method for producing a pneumatic tire by vulcanizing and molding the green tire according to claim 1.

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