JP6657787B2 - Raw tire molding equipment - Google Patents

Description

  The present invention relates to a green tire molding apparatus for joining a case protruding portion to a case body portion expanded in a toroidal shape by a former by pressing the case protruding portion with a turn-up bladder and a pusher.

  For example, in the raw tire shaping step, as shown in FIG. 5A, of the tire case b held on the former a, the case body portion b1, which is an area between the bead cores c, c, is expanded in a toroidal shape. A raw tire is formed by combining the tread d with the tread d waiting on the outside in the radial direction. In this shaping step, the case protruding portion b2, which is a region outside the bead core c in the axial direction outside of the bead core c, is wound up around the bead core c and the toroidal case body portion b1 is used by using a turn-up means. Also, they are pressed against each other to be joined.

  The turn-up means generally includes a turn-up bladder e for winding up the case protruding portion b2 by expansion, and a pusher f for pressing the expanded turn-up bladder e inward in the axial direction. Conventionally, the pusher f includes a ring-shaped side wall portion f1 movable inward and outward in the axial direction, and a peripheral wall portion f2 extending in a straight cylindrical shape from the outer end in the radial direction toward the inside in the axial direction. (See, for example, Patent Document 1).

  However, in such a pusher f having the peripheral wall portion f2 having a right cylindrical shape, as shown in FIG. 5B, when the turn-up bladder e is pressed, a part e1 of the turn-up bladder e becomes part of the peripheral wall portion. Since the pressure P protrudes from f2 and is directed in various directions, the loss increases. As a result, a joint failure between the case protruding portion b2 and the case body portion b1 is likely to occur. In particular, it tends to occur in a tire having a large protruding portion b2 such as a tire having a high flat size.

  In order to improve the bonding failure, the turn-up bladder e needs to be greatly expanded (filling time lengthened). However, in this case, a large load is applied to the driving portion of the pusher f, so that the frequency of occurrence of a failure of the apparatus increases, and a problem that the process time increases due to extension of the filling time also arises.

JP-A-2003-33977

  Therefore, an object of the present invention is to provide a green tire molding apparatus that can reduce a loss of pressing pressure by a turn-up bladder and suppress a joining failure, and can contribute to a reduction in the frequency of occurrence of a failure of the apparatus and a reduction in process time. .

The present invention holds a cylindrical tire case including a carcass, and, among the tire cases, a former for expanding a case body portion between bead cores extrapolated on both sides in the axial direction thereof into a toroidal shape,
Of the tire case, a raw tire forming apparatus comprising a turn-up means for winding up a protruding portion of the case outside the bead core in the axial center direction, and pressing and joining the toroidal case body portion,
The turn-up means presses the rolled-up case protruding portion against the toroidal case body by pressing the expanded turn-up bladder inward in the axial direction, and a turn-up bladder that rolls up the case protruding portion by expansion. And a pusher to join.
The pusher has a ring-shaped side wall portion movably supported in and out of the axial direction, and a conical cylindrical peripheral wall portion that expands inward in the axial direction from a radially outer end of the side wall portion. have a,
The pusher is characterized in that the diameter D1 of the axially inner side surface of the side wall portion is in the range of 150% to 180% of the outer diameter D2 of the turn-up bladder in a non-expanded state .

  In the green tire forming apparatus according to the present invention, it is preferable that the pusher has an angle θ of the peripheral wall portion with respect to an axial line in a range of 20 to 60 degrees.

  In the green tire forming apparatus according to the present invention, the pusher is configured such that an axial width W1 of the peripheral wall portion from an axial inner surface of the side wall portion is an axial center of the turn-up bladder in a non-inflated state. It is preferable that the width is in the range of 20% to 50% of the width W2 in the direction.

  As described above, in the present invention, the peripheral wall of the pusher is formed in a conical cylindrical shape whose diameter increases inward in the axial direction. Therefore, when the turn-up bladder is pressed, it is possible to suppress that a part of the bladder protrudes from the peripheral wall portion and the pressing force is lost. As a result, poor joint between the case protruding portion and the case body can be suppressed. In addition, the time required for filling the turn-up bladder with compressed air can be reduced while suppressing defective joints, thereby shortening the process time and reducing the load on the drive portion of the pusher, thereby reducing the occurrence of device failure. .

It is a top view which shows notionally one embodiment of the raw tire molding apparatus of this invention. It is sectional drawing which expands and shows a part of former. (A) is a sectional view showing a pusher, and (B) is a sectional view showing a turn-up bladder in a non-inflated state. (A), (B) is sectional drawing which shows operation | movement and an effect | action of a pusher. (A), (B) is sectional drawing which shows operation | movement of a conventional pusher and a problem.

Hereinafter, embodiments of the present invention will be described in detail.
As shown in FIG. 1, a green tire forming apparatus 1 of the present embodiment is an apparatus used for a so-called two-stage forming method, and includes a former 2 and a turn-up means 3.

  The former 2 holds a cylindrical tire case A containing a carcass, and forms a bead core B, which is extrapolated on both axial sides of the tire case A, into a case body portion A1, which is a region between the B, in a toroidal shape. Inflate. As a result, the tread T is combined with the tread T that is kept on the outside in the radial direction.

  In this example, a part Aa (inner liner, carcass, etc.) of the tire case A is separately formed on, for example, a band drum (not shown), and after it is transferred to the former 2, the remaining part (bead core B and The case where side wall rubber or the like is formed on the former 2 is shown. However, it is also possible to separately form the entire tire case A on the band drum and transfer it to the former 2. Further, by sequentially winding the tire constituent members including the carcass on the former 2, the tire case A can be directly formed on the former 2 (so-called single-tage molding method).

  The former 2 includes a center shaft 4 and a pair of drums 5 and 5 supported on the center shaft 4 so as to be able to approach and separate from each other in the axial direction. In this specification, the direction toward the tire equator Co, which is the central position in the axial direction between the drums 5 and 5, is defined as the axial direction "inside", and the opposite direction is defined as the axial direction "outside".

  As shown in FIG. 2, the central shaft portion 4 includes a central shaft 6 and a support cylinder 7 which is arranged concentrically on the outside in the radial direction. The center shaft 6 is a screw shaft having a right screw portion and a left screw portion formed on both sides of the tire equator Co, and a nut fitting 8 is screwed to each screw portion.

  The support cylinder 7 is formed with an elongated guide hole 7A extending in the axial direction. A moving body 9 movable in the axial direction is provided in the guide hole 7A. The moving body 9 can move in the axial direction integrally with the nut 8 by the forward and reverse rotation of the center shaft 6 by engaging with the nut 8.

  Next, each of the drums 5 includes a cylindrical drum main body 5A that is slidably mounted on the support cylinder 7 and bead lock means 10 that is supported by the drum main body 5A. The drum body 5A can move integrally with the moving body 9 by being connected to the moving body 9.

  The bead lock means 10 includes a cylinder chamber 13 formed in the drum main body 5A, a piston portion 14 that can move in the cylinder chamber 13 in the axial direction, and a movement of the piston portion 14 in the axial direction. And a bead lock ring 15 that can be enlarged and reduced in diameter in conjunction with it.

  The cylinder chamber 13 has an annular shape concentric with the drum main body 5A. Further, in this example, a cone-shaped bearing surface 14S that is inclined inward in the axial direction and inward in the radial direction is formed at the inner end of the piston portion 14 in the axial direction.

  The bead lock ring 15 is provided in a guide hole 16 formed in the drum main body 5A. The guide hole 16 extends radially outward from the axially inner end of the cylinder chamber 13 and opens on the outer peripheral surface of the drum body 5A.

  The bead lock ring 15 is composed of a plurality of fan-shaped segments 15A divided in the circumferential direction. Each of the segments 15A is guided by the guide hole 16 so as to be movable in and out in the radial direction. A bearing surface 15S inclined at the same gradient as the bearing surface 14S is formed at a radially inner end of each segment 15A. Accordingly, each segment 15A can move in the radial direction in conjunction with the movement of the piston portion 14 in the axial direction, and can expand and contract the bead lock ring 15. A roller may be provided instead of the bearing surface 5S, and the piston portion 14 and each segment 15A may be connected by a link. Reference numeral 17 in the drawing denotes a ring-shaped spring wound in the circumferential direction, and urges each segment 15A inward in the radial direction.

  The former 2 holds the tire case A so as to straddle between the drums 5 and 5. Further, the bead core B of the held tire case A can be fixed by expanding the diameter of the bead lock ring 15. Thereafter, the case body portion A1 can be expanded in a toroidal shape by moving the drums 5, 5 inward in the axial direction and filling the space between the drums 5, 5 with compressed air. Reference numeral 20 in the figure is a shaping flow path for expanding the case body portion A1, and reference numeral 21 is a turn-up flow path for expanding a turn-up bladder 22 described later.

  Next, as shown in FIGS. 4 (A) and 4 (B), the turn-up means 3 winds up a protruding portion A2 of the tire case A, which is an area outside the bead core B in the axial direction, to form a toroid. To the case body portion A1.

  The turn-up means 3 includes a turn-up bladder 22 and a pusher 23. The turn-up bladder 22 winds up the case protruding portion A2 by expansion. Further, the pusher 23 presses the expanded turn-up bladder 22 inward in the axial direction to press the joined case protruding portion A2 against the toroidal case main body portion A1 to join.

  Specifically, as shown in FIGS. 2 and 3 (B), the turn-up bladder 22 has a well-known structure, and extends along the outer peripheral surface of the drum main body 5A in a non-expanded state in which compressed air is not filled. To form a tube that can be folded flat. The turn-up bladder 22 has an extension 24 continuously extending in the circumferential direction on the inner peripheral side. An axially inner opening edge 24i of the opening 24 is fixed to the drum body 5A at a position axially inner than the bead lock ring 15, and an axially inner and outer opening edge 24o is It is fixed to the drum main body 5A at a position outside the ring 15 in the axial direction.

  Further, as shown in FIG. 3 (A), the pusher 23 includes a ring-shaped side wall 25 supported concentrically with the former 2 and movably inward and outward in the axial direction, and a radially outer end of the side wall 25. And a conical cylindrical peripheral wall portion 26 whose diameter increases toward the inside in the axial direction. For the movement of the pusher 23 in the axial direction, similarly to the related art, a driving unit having a well-known structure using a servomotor can be suitably used.

  As shown in FIG. 4 (B), such a pusher 23 can prevent a part of the turn-up bladder 22 from sticking out and losing the pressing force when the turn-up bladder 22 is pressed. As a result, poor joint between the case protruding portion A2 and the case body portion A1 can be suppressed. In addition, it is possible to reduce the time required for filling the turn-up bladder 22 with compressed air and to shorten the process time while suppressing the bonding failure, and to reduce the load on the driving means of the pusher 23 to reduce the occurrence of device failure. Can be.

  As shown in FIGS. 3A and 3B, in the pusher 23, the inclination angle θ of the peripheral wall portion 26 with respect to the axial direction line is preferably in a range of 20 to 60 degrees. When the angle θ is less than 20 degrees or more than 60 degrees, the loss of the pressing force increases.

  In the pusher 23, the axial width W1 of the peripheral wall portion 26 from the axial inner surface of the side wall portion 25 is 20% to 50% of the axial width W2 of the turn-up bladder 22 in the non-expanded state. Is preferably within the range. If the width W1 is less than 20% of the width W2, the space in the pusher 23 becomes too small, so that the turn-up bladder 22 cannot be confined in the pusher 23, and the loss of the pressing force increases. If it exceeds 50%, the space in the pusher 23 becomes excessively large and the turn-up bladder 22 cannot be sufficiently restrained, and the loss of the pressing force increases. Furthermore, the case main part A1 cannot be sufficiently brought close to the case main part A1, which is disadvantageous for joining the case protruding part A2 and the case main part A1.

  In the pusher 23, the diameter D1 of the inner side surface in the axial direction of the side wall portion 25 is preferably in the range of 150% to 180% of the outer diameter D2 of the turn-up bladder 22 in the non-expanded state. When the diameter D1 is less than 150% of the outer diameter D2, the space in the pusher 23 becomes too small, so that the turn-up bladder 22 cannot be confined in the pusher 23, and the loss of the pressing force increases. On the other hand, if it exceeds 180%, the space in the pusher 23 becomes excessively large, so that the turn-up bladder 22 cannot be sufficiently restrained and the loss of the pressing force increases.

  As described above, particularly preferred embodiments of the present invention have been described in detail. However, the present invention is not limited to the illustrated embodiments, and can be implemented in various forms.

  A pusher having a structure shown in FIG. 3A is prototyped according to the specifications shown in Table 1, and a raw tire for a tire size of 245 / 50R19 is manufactured using a raw tire forming apparatus having each pusher (shown in FIGS. 1 and 2). Was formed. Then, when the pusher was pressed against the turn-up bladder to join the protruding portion of the case to the case body, the load applied to the servomotor for driving the pusher was measured and compared with a comparative example. The pusher of the comparative example has a structure shown in FIG. The “load (unit%) applied to the servomotor” is defined as (current value in load state) / (current value in rated state).

A turn-up bladder of the same size is used for each green tire forming apparatus, and its dimensions in the non-inflated state are as follows.
・ Axial width W2: 360mm
・ Outer diameter D2: 493mm

The dimensions of each pusher are as follows.
・ Inner diameter Da of side wall: 472mm
-Side wall width Wa: 29.5 mm
-Angle θ of surrounding wall: Table 1
· Width W1 of the peripheral wall in the axial direction W1: Table 1
-Diameter D1 of the inner side surface in the axial direction of the side wall portion: Table 1

<Joint state>:
The joint between the case protruding portion and the case body was visually inspected. A sample having a good bonding condition was rated as “○”, and a sample having no bonding and a bonding condition having an insufficient bonding were rated “x”.

  In Table 1, the filling time of the compressed air into the turn-up bladder is the same at 8.0 seconds. In addition, in Table 2, the load applied to the pusher driving servomotor and the bonding state when the filling time in the turn-up bladder was changed in the example were checked.

  As shown in Table 1, the embodiment can reduce the load on the servomotor for driving the pusher while suppressing the joint failure between the case protruding portion and the case main body, and reduce the frequency of occurrence of failure of the device and the device. It can be confirmed that it can contribute to the improvement of the life.

  Further, as shown in Table 2, it can be confirmed that the embodiment can reduce the filling time into the turn-up bladder while suppressing the joining failure, and can contribute to the improvement of the production efficiency.

DESCRIPTION OF SYMBOLS 1 Raw tire forming apparatus 2 Former 3 Turn-up means 22 Turn-up bladder 23 Pusher 25 Side wall 26 Peripheral wall A Tire case A1 Case main body part A2 Case protrusion part B Bead core

Claims (3)

A former for holding a cylindrical tire case including a carcass, and for expanding the case body portion between bead cores extrapolated on both sides in the axial direction of the tire case into a toroidal shape,
Of the tire case, a raw tire forming apparatus comprising a turn-up means for winding up a protruding portion of the case outside the bead core in the axial center direction, and pressing and joining the toroidal case body portion,
The turn-up means presses the expanded case protruding portion against a toroidal case body by pressing the expanded turn-up bladder axially inward in the axial direction, and a turn-up bladder that winds the case protruding portion by expansion. And a pusher to join.
The pusher has a ring-shaped side wall portion movably supported in and out of the axial direction, and a conical cylindrical peripheral wall portion that expands inward in the axial direction from a radially outer end of the side wall portion. have a,
The green tire molding apparatus , wherein the pusher has a diameter D1 of an inner surface in the axial direction of the side wall portion in a range of 150% to 180% of an outer diameter D2 of the turn-up bladder in a non-expanded state .   2. The green tire molding apparatus according to claim 1, wherein the pusher has an angle θ of the peripheral wall portion with respect to an axial direction line in a range of 20 to 60 degrees. 3. The pusher has an axial width W1 of the peripheral wall portion from an axial inner surface of the side wall portion in a range of 20% to 50% of an axial width W2 of the turn-up bladder in an unexpanded state. The green tire forming apparatus according to claim 1, wherein:

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