Patent Publication Number: US-2019184663-A1

Title: Method for manufacturing tire component member

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a method for manufacturing a tire component member. 
     Description of the Related Art 
     Generally, a pneumatic tire is manufactured by bonding a plurality of tire component members such as a tread rubber, a sidewall rubber, a carcass ply, a bead, a bead filler, a belt ply and the like on a forming drum to form a green tire, and then by setting the green tire in a mold for vulcanization molding. As a method for forming such a green tire, a ribbon winding method is known in which a strip-shaped ribbon rubber is wound around an outer peripheral surface of a forming drum while being moved in an axial direction of the forming drum, to form the tire component member such as the tread rubber (for example, see JP-A-2002-254531). 
     JP-A-2002-254531 discloses a method in which an average circumferential thickness in a circumferential direction of a forming drum of a ribbon rubber formed by winding the ribbon rubber is calculated, and winding conditions such as a moving distance (so-called feed pitch) for moving the ribbon rubber in the axial direction of the forming drum for each rotation of the forming drum and the number of windings of winding the ribbon rubber around the forming drum are calculated so that a distribution shape of a total added thickness obtained by total addition of the average circumferential thickness is substantially equal to a cross-sectional shape of the tire component member. 
     SUMMARY OF THE INVENTION 
     However, even if the tire component member is formed under forming conditions calculated as in JP-A-2002-254531, the tire component member having a desired shape may not be obtained in some cases. Particularly when the ribbon rubber is wound around the forming drum while extruding the ribbon rubber from an extruder, since the ribbon rubber tends to be deformed, the tire component member having a desired shape may not be obtained from the calculated forming conditions. Therefore, skill and experience by a skilled operator are required in order to determine final forming conditions. 
     The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing the tire component member capable of forming the tire component member having a desired shape by the ribbon winding method without depending on skill and experience of the operators. 
     The method of manufacturing the tire component member of the present invention is a method for manufacturing a tire component member by winding a strip-shaped ribbon rubber around an outer peripheral surface of a forming drum while moving the ribbon rubber in an axial direction of the forming drum. The method of manufacturing the tire component member includes: a first step of setting test conditions including the number of windings of winding the ribbon rubber around the forming drum and a feed pitch for moving the ribbon rubber in the axial direction of the forming drum for each rotation of the forming drum, and a target shape of the tire component member; a second step of preparing the tire component member under the test conditions set in the first step; a third step of measuring a thickness distribution in a width direction of the tire component member prepared in the second step; a fourth step of comparing the measured thickness distribution in the width direction with the target shape to specify a ribbon rubber located at a portion in which a thickness deviation amount exceeds a predetermined range; and a fifth step of changing the feed pitch of the ribbon rubber specified in the fourth step to prepare the tire component member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view showing a configuration of an apparatus for manufacturing a tire component member according to an embodiment; 
         FIG. 2  is a flowchart showing a process of the apparatus for manufacturing the tire component member in  FIG. 1 . 
         FIG. 3  is a cross-sectional view of the tire component member; and 
         FIG. 4  is an enlarged cross-sectional view of a main part of the tire component member. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An embodiment of the present invention will be described below with reference to the drawings. 
       FIG. 1  shows an apparatus (hereinafter also referred to as a manufacturing apparatus)  10  for manufacturing a tire component member according to the present embodiment. 
     The manufacturing apparatus  10  includes a ribbon rubber supply unit  12 , a forming drum  14 , a shape sensor  16 , and a control device  20 . The manufacturing apparatus  10  manufactures a tire component member  50  on the forming drum  14  by a so-called ribbon winding method. In the present embodiment, as the tire component member  50 , a case of forming a substantially cylindrical tread rubber which is provided in a tread portion of a pneumatic tire and constitutes a ground contact surface will be described, however, the present invention can also be applied to the manufacture of tire component members such as a sidewall rubber other than the tread rubber. 
     As shown in  FIG. 3 , the tire component member  50  includes an inner layer  52  composed of a first inner layer  52 A and a second inner layer  52 B, and an outer layer  54  composed of a first outer layer  54 A and a second outer layer  54 B laminated on the outer side of the inner layer  52 . 
     The ribbon rubber supply unit  12  includes an extruder capable of extruding a ribbon rubber  40  into a predetermined cross-sectional shape, and supplies the ribbon rubber to the forming drum while extruding the ribbon rubber from the extruder. A cross-sectional shape of the ribbon rubber  40  is not particularly limited, and various shapes having a flat cross-sectional shape such as a trapezoidal shape, a crescent shape, a triangular shape, or the like can be adopted. A size of the ribbon rubber  40  is not particularly limited, but it can be, for example, 15 to 40 mm in width and 0.5 to 3.0 mm in thickness (thickness in the maximum thickness portion). 
     The forming drum  14  is configured so that it can rotate about a rotation axis and move in an axial direction (direction parallel to the rotation axis). If the forming drum  14  and the ribbon rubber supply unit  12  are relatively movable in the axial direction, the ribbon Lubber supply unit  12  may be configured to be movable in place of the forming drum  14 . 
     The shape sensor  16  is a sensor for measuring an outer shape of the tire component member  50  formed on the forming drum  14 , that is, a thickness distribution in a width direction of the tire component member  50 , in a non-contact state on the forming drum  14 . The width direction of the tire component member  50  is a direction which coincides with an axial direction of the forming drum  14  and is a direction corresponding to a width direction of the tire when constituting the tire together with other members. 
     The shape sensor  16  is the sensor for measuring the tire component member  50  in a non-contact state on the forming drum  14 . For example, a laser displacement sensor for measuring a distance to a reflection surface by irradiating the tire component member  50  formed on the forming drum  14  with a laser beam can be used as the shape sensor  16 . A width, a cross-sectional area, and the thickness distribution in the width direction of the tire component member are measured at a plurality of positions in a circumferential direction of the tire component member  50  at predetermined intervals, and a total value or an average of measurement results at each measurement point can be a measured value of the tire component member. 
     The control device  20  is constituted by a computer or a control microcomputer device including an arithmetic processing unit  21 , a memory  34 , and a display  35 , and is connected to the ribbon rubber supply unit  12 , the forming drum  14 , and the shape sensor  16 . The control device  20  controls an operation of the ribbon rubber supply unit  12 , to supply an unvulcanized strip-shaped ribbon rubber  40  from the ribbon rubber supply unit  12  to the forming drum  14  while rotating the forming drum  14 , so that the ribbon rubber  40  is wound around the forming drum  14  to form the tire component member  50 . 
     Further, the arithmetic processing unit  21  includes a setting input unit  22 , a condition setting unit  24 , a drive control unit  26 , a data acquisition unit  28 , a determination unit  30 , and a correction unit  32 . 
     The setting input unit  22  is a unit to be input with various parameters such as the cross-sectional shape of the ribbon rubber  40  supplied from the ribbon rubber supply unit  12  to the forming drum  14 , a target shape of a cross-section of the tire component member  50 , a winding start position and a winding end position of the ribbon rubber  40 , and a movement pattern of the forming drum  14 , which are used for calculation of the number of windings R and a feed pitch P to be described later. The input various parameters are temporarily stored in the memory  34 . 
     The condition setting unit  24  calculates the number of windings R of winding the ribbon rubber  40  around the forming drum  14  and a moving distance (the feed pitch) P for moving the ribbon rubber  40  in the axial direction of the forming drum  14  for each rotation of the forming drum based on the various parameters input by the setting input unit  22 , and sets the calculated number of windings R and feed pitch P as test conditions. That is, when the number of windings R is N (N: integer, N=41 in  FIG. 3 ) times, feed pitches Pn (n=1, 2, - - - N−1) are set for each turn of the ribbon rubber  40  wound 360 degrees from a winding start end of the ribbon rubber  40 . The feed pitch P is set to be smaller than the width of the ribbon rubber  40  and the ribbon rubber  40  is wound so that at least a part thereof overlaps the adjacent ribbon rubbers  40  in the width direction. 
     The number of windings R and the feed pitch P for each turn obtained by the condition setting unit  24  are input to the drive control unit  26  together with the winding start position and the winding end position of the ribbon rubber  40  and the movement pattern of the forming drum  14 . The number of windings R and the feed pitch P for each turn obtained by the condition setting unit  24  are stored in the memory  34 . 
     The drive control unit  26  controls the operation of the ribbon rubber supply unit  12  and the forming drum  14  based on data input from the condition setting unit  24  and the correction unit  32  to prepare the tire component member  50  and its test sample on the forming drum  14 . 
     In the case illustrated in  FIG. 3 , the ribbon rubber  40  is wound from a winding start end  40 A positioned at the center in the width direction of the forming drum  14  to the eighth turn toward one side W 1  in the width direction of the tire to form the first inner layer  52 A. Further, the ribbon rubber  40  is turned back at an end E 1  on one end side of the forming drum  14  and wound from the ninth turn to the center (21th turn) in the width direction of the tire toward the other side W 2  in the width direction of the tire to form the first outer layer  54 A. Further, the ribbon rubber  40  is continued to be wound to the 28th turn toward the other side W 2  in the width direction of the tire to form the second inner layer  52 B. Furthermore, the ribbon rubber  40  is turned back at an end E 2  on the other side of the forming drum  14  and wound from the 29th turn to the center (41th turn) in the width direction of the tire toward the one side W 1  in the width direction of the tire to form the second outer layer  54 B. That is, in the case of  FIG. 3 , the first inner layer  52 A is formed by the ribbon rubber  40  from the first to eighth turns, the first outer layer  54 A is formed by the ribbon rubber  40  from the ninth to 21th turns, the second inner layer  52 B is formed by the ribbon rubber  40  from the 22nd to 28th turns, and the second outer layer  54 B is formed by the ribbon rubber  40  from the 29th to 41th turns. 
     The data acquisition unit  28  receives a displacement signal (a signal indicating a distance from the sensor to the reflection surface) from the shape sensor  16  and acquires data on a shape of the test sample formed on the forming drum  14 , specifically data on a thickness distribution (an outline shape) in a width direction of the test sample. The acquired data is temporarily stored in the memory  34 . 
     The determination unit  30  reads the data on the thickness distribution in the width direction of the test sample stored in the memory  34  and determines whether the test sample prepared under the test conditions is in the target shape, that is, compares the thickness distributions in the width direction between the test sample prepared under the test conditions and the target shape and determines whether a deviation amount between them is within a predetermined range. 
     The determination unit  30  determines whether the test sample is in the target shape, that is, compares the thickness distribution in the width direction of the measured test, sample and the target shape and determines whether a thickness deviation amount is within the predetermined range. When there is a portion in which the thickness deviation amount exceeds the predetermined range, the ribbon rubber  40  located at the portion is specified. That is, it is specified which turn of the ribbon rubber  40  is located at the portion in which the thickness deviation amount exceeds the predetermined range Then, the determination unit  30  inputs the result to the correction unit  32 . 
     The correction unit  32  determines forming conditions of the tire component member  50  to be prepared next based on an input from the determination unit  30 , and inputs the forming conditions to the drive control unit  26 . A method of determining the forming conditions of the tire component member  50  to be prepared next will be described later. 
     Next, a process flow according to the present embodiment will be described with reference to  FIG. 2 . 
     First, the various parameters such as the cross-sectional shape of the ribbon rubber  40  supplied from the ribbon rubber supply unit  12  to the forming drum  14 , and the target shape of the cross-section of the tire component member  50 , which are used for calculation of the number of windings R and the feed pitch P, are input to the setting input unit  22  (Step S 10 ). 
     Next, the condition setting unit  24  calculates the number of windings R and the feed pitch P depending on the target shape based on the various parameters input to the setting input unit  22 , and acquires the test conditions (Step S 11 ). 
     Next, the drive control unit  26  controls the operation of the ribbon rubber supply unit  12  and the forming drum  14  based on the test conditions calculated by the condition setting unit  24 , and prepares the test sample of the tire component member  50  on the forming drum  14  (Step S 12 ). 
     Next, the shape sensor  16  measures the width, the cross-sectional area, and the thickness distribution in the width direction of the test sample of the tire component member  50  prepared on the forming drum  14 , and the data acquisition unit  28  acquires the measurement results (Step S 13 ). 
     Next, the determination unit  30  compares the thickness distributions in the width direction between the test sample prepared under the test conditions and the target shape, and determines whether the thickness deviation amount is within the predetermined range (Step S 14 ). Then, when there is the portion in which the thickness deviation amount exceeds the predetermined range (No in Step S 14 ), the ribbon rubber  40  located at the portion in which the thickness deviation amount exceeds the predetermined range is specified (Step S 15 ). 
     For example, as exemplified in  FIG. 4 , when a thickness of the test sample exceeds the predetermined range with respect to an outer diameter line L of the target shape in a region F 1 , and the thickness falls below the predetermined range with respect to the outer diameter line L of the target shape in a region F 2 , the ribbon rubber  40  at the 25th, 26th, and 30th to 33rd turns from the winding start end  40 A is specified as the ribbon rubber  40  located at positions in which the thickness is excessive, and the ribbon rubber  40  at the 24th, and 34th to 36th turns from the winding start end  40 A is specified as the ribbon rubber  40  located at positions in which the thickness is insufficient. 
     When the determination unit  30  specifies the portion in which the thickness deviation amount exceeds the predetermined range, the correction unit  32  adjusts the feed pitch P of the ribbon rubber  40  at the specified position to calculate a correction condition (Step S 16 ). As a method of calculating the correction condition in this case, the feed pitch P of the ribbon rubber  40  at the position in which the thickness is insufficient is reduced, and the feed pitch P of the ribbon rubber  40  at the position in which the thickness is excessive is increased. An amount of change in the feed pitch P can be changed depending on a deviation of the thickness between the test sample and the target shape. 
     When the correction unit  32  calculates the correction condition in Step S 16 , the process returns to Step S 12  again, and the drive control unit  26  controls the operation of the ribbon rubber supply unit  12  and the forming drum  14  based on the correction condition calculated by the correction unit  32  to prepare a second test sample of the tire component member  50  on the forming drum  14 . 
     Thereafter, preparation (Step S 12 ), measurement (Step S 13 ), evaluation (Steps S 14 , S 15 ) of the test sample, and calculation of the correction condition (Step S 16 ) are repeated until the deviation amount of the thickness distribution in the width direction between the test sample and the target shape falls within the predetermined range. When the deviation amount of the thickness distribution in the width direction between the test sample and the target shape is within the predetermined range (Yes in Step S 14 ), the correcting unit  32  determines that the prepared test sample is in the target shape, and sets the test conditions or the correction condition without modification, so that the tire component member  50  is manufactured under this condition. 
     According to the present embodiment, it is possible to obtain the tire component member  50  by winding the ribbon rubber around the outer peripheral surface of the forming drum while moving the ribbon rubber in the axial direction of the forming drum without requiring skill and experience by a skilled operator. 
     Further, in the present embodiment, since the width, the cross-sectional area, and the thickness distribution in the width direction of the test sample of the tire component member  50  formed on the forming drum  14  are measured in a non-contact state, it is possible to accurately measure the test sample without deformation during the measurement. 
     The above embodiment is presented as an example and is not intended to limit the scope of the invention. This novel embodiment can be implemented in various other forms and various omissions, substitutions, and changes can be made without departing from the gist of the invention. 
     For example, in the present embodiment, a description is given of a case where the ribbon rubber  40  is directly wound around the outer peripheral surface of the forming drum  14  to prepare the test sample of the tire component member  50 . However, for example, the test sample of the tire component member  50  may be provided on another tire component member already provided on the outer peripheral surface of the forming drum  14 . In this case, the shape of the outer peripheral surface of the forming drum  14  is measured before preparing the test sample of the tire component member  50 , and a difference between the measurement result after the test sample is prepared and the measurement result before the test sample is prepared may be used as a measured value. 
     In the present embodiment, the number of windings R and the feed pitch P calculated by the condition setting unit  24  based on the various parameters input by the setting input unit  22  are set as the test conditions, however, conditions directly input by the operator may be set as the test conditions, or previously used conditions may be set as the test conditions. 
     Further, in the present embodiment, a description has been given of a case where when there is the portion in which the thickness deviation amount exceeds the predetermined range between the test sample prepared under the test conditions by the determination unit  30  and the target shape, the correction unit  32  newly calculates the correction condition. However, for example, when the determination unit  30  specifies the ribbon rubber  40  located at a position in which the thickness of the test sample exceeds or falls below the predetermined range with respect to the target shape, the position and the deviation amount of the specified ribbon rubber  40  may be displayed on the display  35  to urge the operator to correct the test, conditions and the condition directly input by the operator may be used as the correction condition. 
     DESCRIPTION OF REFERENCE NUMERALS AND SIGNS 
       10 : manufacturing apparatus,  12 : ribbon rubber supply unit,  14 : forming drum,  16 : shape sensor,  20 : control device,  21 : arithmetic processing unit,  22 : setting input unit,  24 : condition setting unit,  26 : drive control unit,  23 : data acquisition unit,  30 : determination unit,  32 : correction unit,  34 : memory,  35 : display,  40 : ribbon rubber,  50 : tire component member,  52 : inner layer,  54 : outer layer.