JP2015205480A - Manufacturing method of pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the quality of a tire by reducing changes in thickness at a joint portion when forming an annular tire constituent member by joining both ends of a belt-like rubber member together.SOLUTION: A manufacturing method of a pneumatic tire includes a joining step of forming a tire constituent member into an annular shape by overlapping and joining cut surfaces S1 of a belt-like rubber member 1 having cut surfaces S1 at both ends in a longitudinal direction. The cut surface S1 is formed of an inclined surface 11 in which an intersection angle α between the belt-like rubber member 1 and a bottom surface S2 is in a range of 10-18 degrees. The rubber member is cut by moving a cutter blade 6 parallely on the inclined surface 11 in a travel direction K which is inclined at an angle β with respect to a width direction line x.

Description

  The present invention relates to a method for manufacturing a pneumatic tire capable of improving tire quality by reducing a change in thickness at a joining portion when both ends of a belt-like rubber member are joined to form an annular tire constituent member.

  In the production process of raw tires, for example, when forming tire components such as sidewall rubber and tread rubber in an annular shape, a belt-shaped rubber member having cut surfaces at both ends in the longitudinal direction is wound around the drum once, and then the cut surfaces Are overlapped and joined (for example, refer to Patent Document 1). At this time, as shown in FIGS. 10A and 10B, in order to increase the bonding strength at the bonding portion A, the cut surfaces bs at both ends of the belt-like rubber member b are, for example, 35 to 60 degrees with respect to the bottom surface. It is inclined at an angle α.

  Also, as shown in FIG. 10A, in the joint A, when the overlap amount between the cut surfaces bs and bs is less than the reference J by ΔW1, the joint area is reduced. The risk of coming off increases. For this reason, conventionally, as shown in FIG. 10B, the overlap amount is set larger than the reference J to prevent the joining portion A from coming off. However, in this case, there is a problem that the excess ΔW2 of the overlap amount causes a non-uniform thickness such as the occurrence of a convex raised portion C, thereby reducing the tire quality.

  Therefore, the present inventor has proposed to reduce the angle α of the cut surface bs to a range of 10 to 18 degrees. Thereby, the thickness change of the joint portion A becomes gradual, the protruding amount of the raised portion C can be kept small, and the joint area becomes large, which is advantageous for the detachment of the joint portion. However, when the angle α is reduced to the above range, the contact resistance between the cutter blade and the rubber member increases, and the cut edge is disturbed, or the cut is not good, such as the rubber is not cut in the later stage of cutting. There will be new problems to be solved.

JP 2003-11245 A

  Therefore, the present invention is based on moving the cutter blade on the inclined surface in the traveling direction inclined at an angle β with respect to the width direction line x, so that both ends of the belt-shaped rubber member are 10 to 10 without causing cutting failure. It is an object of the present invention to provide a method of manufacturing a pneumatic tire that can be cut at an angle α of 18 degrees and can improve tire quality by reducing a change in thickness at a joint portion.

The present invention includes a joining step of forming a tire component member in an annular shape by joining the cut surfaces of a belt-shaped rubber member having cut surfaces at both ends in the longitudinal direction and being wound around on the drum. A method for manufacturing a pneumatic tire including:
The band-shaped rubber member is formed by sequentially cutting a long rubber material with a cutter blade,
Moreover, in the cut surface, the cross line where the cut surface and the bottom surface of the belt-shaped rubber member intersect is parallel to the width direction line x of the belt-shaped rubber member, and the cross angle α between the cut surface and the bottom surface is 10 It consists of an inclined surface in the range of ~ 18 degrees,
The cutter blade is characterized in that the rubber material is cut by moving in parallel on the inclined surface in a traveling direction inclined at an angle β with respect to the width direction line x.

  In the method for manufacturing a pneumatic tire according to the present invention, the angle β in the traveling direction is preferably 3 degrees or more.

  As described above, according to the present invention, the cross-section line between both ends of the band-shaped rubber member is parallel to the width direction line x and the crossing angle between the cut plane and the bottom surface of the band-shaped rubber member. α is an inclined surface of 10 to 18 degrees. For this reason, when joining the cut surfaces with each other, even if the overlap amount is large, the thickness change of the joint portion becomes gradual, and the protruding amount of the raised portion is suppressed to improve the tire quality. it can. Further, since the bonding area is increased, the bonding strength can be increased.

  Moreover, with respect to the formation of the cut surface, the cutter blade is translated on the inclined surface in the traveling direction inclined at an angle β with respect to the width direction line x. Thereby, even when the crossing angle α is reduced to the above range, it is possible to suppress cut defects such as distorted cuts and torn pieces of rubber, suppression of the above-described thickness change of the joint portion, improvement of tire quality, etc. The effect can be achieved.

It is a schematic diagram which shows the manufacturing method of the pneumatic tire of this invention. It is a perspective view which shows a cut surface with the cutting method. (A), (B) is a perspective view which shows the mechanism of this invention. It is a perspective view which shows the other mechanism of this invention. (A), (B) is sectional drawing which compared the effect of this invention with the comparative example. It is a side view of a cutting device. It is a top view of a cutting device. It is a front view of a cutting device. It is a perspective view which shows the principal part of a cutting device. (A), (B) is sectional drawing which shows the junction part of the conventional strip | belt-shaped rubber member.

Hereinafter, embodiments of the present invention will be described in detail.
As shown in FIG. 1, the pneumatic tire manufacturing method of the present invention has the cut surfaces S <b> 1 and S <b> 1 of the belt-like rubber member 1 having cut surfaces S <b> 1 at both ends in the longitudinal direction and wound once on the drum 2. Including a joining step of forming the tire constituent members in an annular shape by superimposing them together.

  The tire constituent member is, for example, a sidewall rubber, a tread rubber, a chafer rubber (bead rubber), and the rubber composition, a cross-sectional shape, a dimension, and the like of the belt-like rubber member 1 are different depending on the tire constituent member to be formed. The belt-like rubber member 1 is formed by sequentially cutting a long rubber material 4 having a predetermined cross-sectional shape, which is extruded by a rubber extruder, with a cutter blade 6 of a cutting device 5.

  In this example, the rubber material 4 whose length direction front end Ea has been cut first is supplied to the drum 2 side and winding is started. The drum 2 is stopped when a length corresponding to one round is supplied, and the rubber material 4 is cut to cut the rear end. That is, in this example, the case where formation and winding of the belt-like rubber member 1 are performed simultaneously is shown. However, the present invention is not limited to this, and the rubber material 4 is sequentially cut in advance to form the belt-like rubber member 1. Thereafter, the formed belt-like rubber member 1 is supplied to the drum 2 side and wound once. You can also.

  As conceptually shown in FIG. 2, in the cut surface S <b> 1, the intersecting line 10 where the cut surface S <b> 1 and the bottom surface S <b> 2 of the belt-like rubber member 1 intersect is parallel to the width direction line x of the belt-like rubber member. Moreover, the cut surface S1 is formed as the inclined surface 11 having an intersecting angle α between the cut surface S1 and the bottom surface S2 of 10 to 18 degrees.

  This cutting surface S1 has a cutting edge 6e directed in the width direction, and the cutting blade 6 is directed in the width direction toward a traveling direction K inclined on the inclined surface 11 at an angle β with respect to the width direction line x. It is formed by translating from one side to the other. The cutter blade 6 is a thin flat non-rotating cutter, and a conventional cutter blade can be suitably used. The cutter blade 6 is attached with its length direction substantially perpendicular to the width direction line x.

  Here, the following effects are produced by inclining the advancing direction K of the cutter blade 6 with respect to the width direction line x. For example, as schematically shown in FIG. 3A, when the traveling direction K and the width direction line x are the same, the cutter blade 6 can apply a shearing force Fx in the x-axis direction to the rubber material 4. it can. On the other hand, when the traveling direction K is inclined with respect to the width direction line x, as schematically shown in FIG. 3B, the shear force Fx in the x-axis direction and the shear force Fz in the z-axis direction The resultant force Fxz can be applied to the rubber material 4. That is, the rubber material 4 can be cut with a larger shearing force Fxz, and excellent cutting performance can be exhibited. The angle β is preferably 3 degrees or more, and if the angle β is less than 3 degrees, the above effect is reduced and it becomes difficult to sufficiently suppress cut defects. As the angle β increases, the shear force Fxz increases, but the amount of displacement of the cutter blade 6 in the z-axis direction until the cutting is completed increases. For this reason, in the case of a production line in which the formation and winding of the belt-like rubber member 1 are performed simultaneously as in this example, the degree of freedom of adoption is greatly limited, such as the possibility of the cutter blade 6 and the drum 2 colliding with each other. Therefore, the upper limit of the angle β is preferably 17 degrees or less, and more preferably 15 degrees or less.

  As shown in FIG. 4, the blade edge 6 e is preferably inclined with respect to the traveling direction K at an angle θ of less than 90 degrees, more preferably 80 degrees or less. In this case, the apparent blade angle γ1 of the cutter blade 6 is smaller than the actual blade angle γ0. That is, since the cutting edge is apparently sharp, the sharpness is increased, and in combination with the increase in the shearing force Fxz, more excellent cutting performance can be exhibited. As a result, even when the intersection angle α is reduced to a range of 10 to 18 degrees, it is possible to suppress cut defects. Moreover, as shown in FIGS. 5A and 5B, for example, in the case of the example in which the crossing angle α is 18 degrees (shown in FIG. 5A), in the case of the comparative example in which the crossing angle α is 30 degrees. Compared to (shown in FIG. 5B), when the overlap amount ΔW2 of the overlap is the same, the protrusion amount H of the raised portion C at the joint A can be significantly suppressed, and the thickness uniformity is increased. sell.

  Next, an example of the cutting device 5 is shown in FIGS. The cutting device 5 of this example includes a cutter blade 6 and a moving tool 7 that moves the cutter blade 6 in the traveling direction K on the inclined surface 11 (shown in FIG. 2). Supported by The rubber material 4 is carried into the cutting device 5 via a conveyor 9 (shown in FIG. 1).

  The frame 8 of this example includes a first frame 8A and a second frame 8B that is pivotally supported by a support shaft 15 provided on the first frame 8A and whose front end side can tilt up and down. The second frame 8B moves up and down between a cutting position P1 for cutting the rubber material 4 and a supply position P2 (not shown) for supplying the front end side of the cut rubber material 4 to the drum 2 by the tilting. Can be repositioned. Further, a cradle 16 for receiving the bottom surface S2 of the rubber material 4 at the time of cutting is attached to the second frame 8B.

  The moving tool 7 is attached to the first frame 8A. The moving tool 7 includes a guide means 17 supported by the first frame 8A, a moving base 18 that is guided by the guide means 17 and moves forward and backward in the advancing direction K, and in this example, an elevating means 19 is provided on the moving base 18. And a cutter holder 20 to be attached.

  As shown in FIG. 9, the guide means 17 of the present example includes a guide shaft 21 and a ball screw shaft 22 extending in the traveling direction K and parallel to each other. The guide shaft 21 and the ball screw shaft 22 are supported via a mounting plate 23 that spans between the side plates 8A1 of the first frame 8A. The ball screw shaft 22 is rotationally driven by a motor M fixed to the mounting plate 23.

  The moving table 18 includes a guide hole 18A through which the guide shaft 21 is inserted and a screw hole 18B into which the ball screw shaft 22 is screwed, and can move in the traveling direction K by the rotation of the ball screw shaft 22.

  The elevating means 19 is a cylinder 19A in this example, and the cutter holder 20 is supported at the lower end of the rod via an elevating plate 24 so as to be movable up and down. The cutter holder 20 holds the rear end portion of the cutter blade 6. At this time, the cutter blade 6 is attached along the inclined surface 11 (shown in FIG. 2) and the blade edge 6e is directed in the width direction.

  The moving tool 7 of this example includes a pressing roller 25. The presser roller 25 is disposed on the front side in the moving direction K of the cutter blade 6 and presses the rubber material 4 during cutting. The presser roller 25 is pivotally supported at the lower end of the rod of the cylinder 26 so as to roll in the traveling direction K. The cylinder 26 is attached to the elevating plate 24 via a mounting plate 27 and can move together with the cutter blade 6.

  In this cutting device 5, when the cutter blade 6 is lowered by the elevating means 19, the moving tool 7 is operated to move the cutter blade 6 in parallel in the traveling direction K from one side in the width direction to the other side. Thereby, the rubber material 4 can be cut along the inclined surface 11. At this time, the advancing direction K is inclined at an angle β with respect to the width direction line x, so that cutting is smooth and cut defects are suppressed. At the time of cutting, the presser roller 25 presses the rubber material 4 against the cradle 16 due to the extension of the cylinder 26, thereby preventing the rubber material 4 from being displaced.

  After cutting, the cutter blade 6 is raised by the lifting means 19 so that the cutter blade 6 can be returned to the one side from the other side in the width direction and can be prepared for the next cutting.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

  A raw tire for a passenger car having a tire size of 205 / 60R16 was formed based on the manufacturing method of the present invention using the apparatus shown in FIGS. And in each sample tire, the uniformity of the junction part in sidewall rubber (tire constituent member) was measured. Table 1 shows the specifications for joining the sidewall rubber. Except as described in Table 1, the specifications are substantially the same, and the overlap surplus amount ΔW2 of the joint is the same for each tire.

(1) Uniformity of the joint part;
Five raw tires were respectively formed, and as shown in FIG. 5, the maximum value of the protrusion amount H of the raised portion C at the junction A of the sidewall rubber was measured and evaluated by the average value. The smaller the value, the better the thickness uniformity.

  As shown in the table, it can be confirmed that the examples are excellent in thickness uniformity at the joint. In Example 4, since cutting failure occurred in one of the five tires, the average value of the four tires is shown. In Comparative Examples 1 to 3, since the intersection angle α is large, the protrusion amount H is large and the thickness uniformity is poor. In Comparative Example 4, since the intersection angle α was too small, the angle β (15 degrees) was attached in the traveling direction, but the cutting was not possible. In Comparative Example 5, the crossing angle α was 14 degrees, but the cutting was not possible because there was no angle β in the traveling direction. In Example 4, since cutting failure occurred in one of the five tires, the average value of the four tires is shown. In Example 9, since the cutter blade becomes long, the drum and the blade interfere with each other and cannot be implemented in this example. However, this can be implemented in the case of a production line in which the process of forming the band-shaped rubber member by cutting and the process of winding the band-shaped rubber member around the drum are performed separately.

DESCRIPTION OF SYMBOLS 1 Band-shaped rubber member 2 Drum 4 Rubber material 6 Cutter blade 10 Crossing line 11 Inclined surface K Traveling direction S1 Cutting surface S2 Bottom surface

Claims (2)

A pneumatic tire including a joining step of forming a tire constituent member in an annular shape by joining the cut surfaces of a belt-like rubber member having cut surfaces at both ends in the longitudinal direction and being wound around on the drum. A manufacturing method of
The band-shaped rubber member is formed by sequentially cutting a long rubber material with a cutter blade,
Moreover, in the cut surface, the cross line where the cut surface and the bottom surface of the belt-shaped rubber member intersect is parallel to the width direction line x of the belt-shaped rubber member, and the cross angle α between the cut surface and the bottom surface is 10 It consists of an inclined surface in the range of ~ 18 degrees,
The method of manufacturing a pneumatic tire according to claim 1, wherein the cutter blade cuts the rubber material by moving in parallel on the inclined surface in a traveling direction inclined at an angle β with respect to the width direction line x. The method of manufacturing a pneumatic tire according to claim 1, wherein the traveling direction angle β is 3 degrees or more.

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