JP2012166468A - Method and apparatus for tire molding - Google Patents

Abstract

A tire molding method capable of molding a tire easily and accurately by sequentially winding a strip rubber around the surface of a molding drum having a curved surface corresponding to the shape of the inner surface of the tire without requiring a complicated stitcher control mechanism. A tire molding apparatus is provided.
A tire molding method for molding a tire by sequentially winding a strip rubber S around a surface 1b of a molding drum 1 having a curved surface corresponding to a tire inner surface shape, and the strip rubber S has a round cross-sectional shape. .
[Selection] Figure 5

Description

  The present invention relates to a tire molding method and a tire molding apparatus for molding a tire by sequentially winding a strip rubber around a surface of a molding drum having a curved surface corresponding to a tire inner surface shape.

  While supplying strip rubber having a predetermined cross-sectional shape onto a rotationally driven molding drum, the strip rubber is moved in the direction of the drum axis (rotating axis) of the molding drum, and the strip rubber is layered on the outer surface of the molding drum. There is known an apparatus for forming a tire having a predetermined profile by wrapping around a tire (see Patent Documents 1 and 2 below).

  The strip rubber used in Patent Document 1 has a cross section in which the thickness of at least one width direction end is substantially zero, and the thickness gradually decreases from the position of the maximum thickness in the width direction toward the end. It has a shape. Patent Document 2 is characterized in that unvulcanized rubber is extruded into a tubular cross section to form a rubber tube, and this tube is pressed onto the core with a roller and flattened to form a plate-like strip rubber. Yes.

International Publication No. 02/078939 JP 2002-160282 A

  However, when the side portion of the tire is molded with a plate-shaped strip rubber as in Patent Document 1, the tension of the strip rubber is not constant due to the difference between the inner and outer circumferences in the width direction, and variations in thickness and width occur. There is concern about deterioration of accuracy. Further, when molding a side portion of a tire, particularly a side portion that is a concave portion, the end portion in the width direction of the strip rubber is warped and cannot be applied well. Therefore, when the strip rubber is pressed and molded by a stitcher or the like, it is necessary to move the stitcher along the curved surface shape and adjust the angle of the roller, which requires a complicated stitcher control mechanism.

  On the other hand, as in Patent Document 2, it is very difficult to form a tube of unvulcanized rubber. Furthermore, since the tube is crushed with a roller to form a plate shape, the size and shape of the roller when pasting on a recess In some cases, the roller is in point contact with only a part of the tube, and cannot be crushed uniformly, and there is a concern about deterioration of molding accuracy.

  The present invention has been made in view of the above circumstances, and it is easy to wrap a strip rubber around the surface of a molding drum having a curved surface corresponding to the tire inner surface shape without requiring a complicated stitcher control mechanism. It is another object of the present invention to provide a tire molding method and a tire molding apparatus capable of molding a tire with high accuracy.

In order to solve the above problems, the tire molding method according to the present invention is:
A tire molding method for molding a tire by sequentially winding a strip rubber around the surface of a molding drum having a curved surface corresponding to a tire inner surface shape,
The strip rubber has a round cross-sectional shape.

  The effects of the tire molding method having such a configuration will be described. A strip rubber having a round cross-sectional shape can be easily formed as compared with a plate-like or tube-like rubber. Further, by using a strip rubber having a round cross-sectional shape, there is little variation in tension due to the difference between the inner and outer circumferences even when wound, and the molding accuracy is improved as compared with the case of using other cross-sectional shapes. Furthermore, when the strip rubber is wound around the molding drum, the plate-like strip rubber has a warped end in the width direction and does not stick to the molding drum, and a complicated stitcher control mechanism is required to press it. The strip rubber having a round cross-sectional shape can be easily attached with a simple stitcher. Therefore, there is provided a tire molding method capable of easily and accurately molding a tire by sequentially winding a strip rubber around the surface of a molding drum having a curved surface corresponding to the tire inner surface shape without requiring a complicated stitcher control mechanism. can do. The round shape is a concept including a circle, an ellipse, an oval, and the like.

  In the present invention, it is preferable to wind adjacent strip rubbers while overlapping each other. As a result, the gap between the strip rubbers can be reduced to prevent entry of air, so that the tire can be accurately molded.

  In the present invention, it is preferable to wind the strip rubber and mold the side portion of the tire. When the side portion of the tire is molded using a plate-shaped strip rubber, the molding accuracy deteriorates due to the difference between the inner and outer circumferences. However, according to the present invention, the side portion of the tire can be molded easily and accurately.

  In the present invention, the side portion preferably includes a rim strip. The rim strip of the tire has a concave portion, and the end in the width direction is warped with a plate-shaped strip rubber and cannot be attached well. However, according to the present invention, the rim strip can be easily and accurately molded. it can.

Moreover, in order to solve the said subject, the tire shaping | molding apparatus which concerns on this invention is
A tire molding apparatus comprising a molding drum having a curved surface corresponding to a tire inner surface shape and an extruder for extruding a strip rubber from a die, and molding the tire by sequentially winding the strip rubber around the surface of the molding drum,
The base has a discharge port through which a strip rubber having a round cross-sectional shape can be extruded.

  The effects of the tire molding apparatus having such a configuration are as described above. According to the present invention, a strip is formed on the surface of the molding drum having a curved surface corresponding to the tire inner surface shape without requiring a complicated stitcher control mechanism. A tire can be easily and accurately molded by winding rubber sequentially.

Diagram showing the layout relationship between the molding drum and the extruder (schematic diagram) Side view showing schematic layout of molding drum and extruder (schematic diagram) Schematic diagram showing the configuration of the roll drive unit Diagram explaining the strip rubber application process (viewed in drum axis direction) Figure explaining the strip rubber application process (viewed from the cross section of the forming drum)

  A preferred embodiment of a tire molding apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the positional relationship between a molding drum and an extruder, and is (a) a front view, (b) a side view, and (c) a plan view.

<Configuration of tire molding device>
In FIG. 1, the molding drum 1 is configured to be rotationally driven around a drum shaft 1a. The molding drum 1 has a drum surface 1b formed in a three-dimensional curved surface shape corresponding to the tire inner surface shape. On the other hand, the extruder 2 extrudes the strip rubber S from the die 22. By sequentially winding the strip rubber S around the molding drum 1, a tire having a desired cross-sectional shape can be molded.

  Here, the relative positional relationship between the molding drum 1 and the extruder 2 varies depending on the drive mechanism that drives the molding drum 1 and the extruder 2. The extruder 2 can move in the forward and backward directions (x direction) with respect to the molding drum 1. Further, the molding drum 1 can move in a horizontal direction (y direction) orthogonal to the x direction. Further, the molding drum 1 can rotate not only around the drum shaft 1a (α direction) but also in the θ direction and the φ direction. The θ direction is a direction in which the molding drum 1 is inclined with respect to the vertical axis z between the side approaching the extruder 2 and the side away from the extruder 2, and the φ direction is a direction in which the molding drum 1 turns in a horizontal plane. However, the extruder 2 may be fixed and only the molding drum 1 may be moved, or the molding drum 1 may be fixed and only the extruder 2 may be moved. With the configuration as described above, the strip rubber S can be sequentially wound around the surface 1b of the molding drum 1 having a curved surface corresponding to the tire inner surface shape.

  FIG. 2 is a side view (schematic diagram) showing an arrangement relationship between the molding drum 1 and the extruder 2. The extruder 2 includes a base 22, a gear pump 20, and a screw 21. The gear pump 20 includes two gears and supplies a predetermined amount of rubber toward the base 22. The screw 21 kneads rubber. In FIG. 2, the two gears of the gear pump 20 are arranged side by side in the vertical direction for convenience of illustration, but are actually arranged side by side in the plane direction (the direction in which the rotation axis of the gear is up and down).

  The base 22 includes a discharge port 22a through which the strip rubber S having a round cross-sectional shape can be extruded. In the present embodiment, the opening of the discharge port 22a is circular, but may be oval or oval. Since the base 22 can have a pointed tip, the merit is great for approaching the curved surface of the molding drum 1, particularly the curved surface that is a recess.

  The strip rubber S extruded from the extruder 2 is supplied in the direction of arrow D, and is sequentially wound around the outer peripheral surface of the molding drum 1 (direction of arrow E). An affixing roll 3 for pressing and adhering the strip rubber S to the drum surface of the molding drum 1 is provided. The affixing roll 3 also has a role of strengthening the adhesive force between the strip rubbers S. The affixing roll 3 can move between a position close to the forming drum 1 and a position separated from the forming drum 1 (arrow F). The affixing roll 3 is not limited to a flat shape but may be a crown shape. The surface of the sticking roll 3 may be knurled.

  The molding drum 1 is provided with a drum driving mechanism 4 for causing the above-described complicated movement, and is controlled by a control device 5. The drum drive mechanism 4 includes elements such as a servo motor and a linear guide. The gear pump 20 and the screw 21 of the extruder 2 are also driven by the drive mechanism 6 and controlled by the control device 5. Similarly, the drive mechanism 6 can be driven with high precision by a servo motor or the like. The affixing roll 3 and its roll driving unit 30 are attached to the main body 2a constituting the extruder 2.

<Configuration of roll drive unit>
Next, the structure of the roll drive part 30 is demonstrated with the schematic diagram of FIG. The affixing roll 3 is supported by a support 31 via a support arm 32. The affixing roll 3 is rotatably supported at the end 32 a of the support arm 32. The other end 32 b of the support arm 32 is fixed to the support 31. Since the support 31 and the support arm 32 are fixed to each other, they move while maintaining the same posture. In order to easily press the surface of the molding drum 1, the support arm 32 is attached in an oblique posture so as to be directed toward the molding drum 1.

  The support 31 is guided by a guide portion 33 so as to be movable in the direction of arrow A. An air cylinder 34 is provided so that the whole including the guide portion 33 and the pasting roll 3 can move in the arrow B direction. By means of the air cylinder 34, the sticking roll 3 can be switched between a position close to the molding drum 1 and a position separated from the forming drum 1. Control of the air cylinder 34 is performed by a computer program incorporated in the control device 5.

  The support 33 is always urged by the air cylinder 35 in the direction of pressing the surface of the molding drum 1. Thereby, when affixing the strip rubber S, an appropriate pressing force can be applied. The distance between the affixing roll 3 and the surface 1b of the molding drum 1 (the surface of the strip rubber S that has already been affixed) fluctuates during the affixing process. be able to.

<Strip rubber winding process>
Next, the winding process of the strip rubber S will be described. In this embodiment, an example of molding a rim strip of a tire is shown. Further, in the present embodiment, an example in which a tire constituent member 10 such as a bead portion 11 made of beads and a bead filler, a carcass ply 12 and an inner liner rubber 13 is already molded on the surface 1b of the molding drum 1 is shown. The tire of the present embodiment can be molded in the same manner as a conventional tire molding process, except for the points relating to the rim strip described below. FIG. 4 is a diagram for explaining the operation when viewed from the direction of the drum shaft. FIG. 5 is a diagram for explaining the operation when viewed from the cross-sectional direction of the molding drum.

  FIG. 4A shows the start of the winding process. First, the die 22 of the extruder 2 is brought into close contact with the surface of the molding drum 1 (or the surface of the tire constituent member 10 already attached). At this time, the sticking roll 3 is in the retracted position so as not to get in the way. When the extrusion of the strip rubber S is started, the interval between the extruder 2 and the molding drum 1 is widened.

  During the winding process of the strip rubber S, the affixing roll 3 is urged against the surface of the molding drum 1 and therefore always has a positional relationship as shown in (b). (C) is a figure which shows a mode when the sticking process of strip rubber | gum S is complete | finished. Since it is necessary to cut the strip rubber S at the end of the process, it is necessary to bring the extruder 2 close to the surface of the molding drum 1 again. At this time, since it interferes with the affixing roll 3, the air cylinder 34 is driven and moved from the close position to the retracted position.

  In the present embodiment, the strip rubber S is sequentially wound around the surface 1b of the molding drum 1 to mold the rim strip. The strip rubber S is spirally wound around the side surface of the molding drum 1 along the circumferential direction. FIG. 5A is an initial stage of the winding process, and is a state in which the strip rubber S is wound a plurality of times. At this time, the adjacent strip rubbers S are wound while being overlapped with each other as shown in the enlarged view of FIG. The diameter d of the strip rubber S is preferably 0.5 to 3.0 mm. The overlap amount OL is preferably 0.1 to 1.0 mm, more preferably 0.1 to 0.5 mm.

  Next, FIG. 5B shows a state in which the strip rubber S is wound and the rim strip 14 having a desired cross-sectional shape is molded. The rim strip 14 is then molded with a tread rubber, sidewall rubber, or the like to form a tire. However, the molding order of each tire constituent member can be changed as appropriate.

<Another embodiment>
In the above-described embodiment, an example in which a rim strip is molded has been described. However, other tire components can also be molded using the tire molding method and the tire molding apparatus of the present invention. For example, when a plate-like strip rubber is used as a sidewall rubber of a tire, molding accuracy may be deteriorated due to a difference between inner and outer circumferences. However, according to the present invention, molding can be easily and accurately performed.

  In this embodiment, although the extruder 2 is a structure provided with the gear pump 20, the extruder 2 which is not provided with the gear pump 20 may be used.

DESCRIPTION OF SYMBOLS 1 Molding drum 1b Drum surface 2 Extruder 3 Sticking roll 14 Rim strip 20 Gear pump 21 Screw 22 Base 22a Discharge port S Strip rubber

Claims (5)

A tire molding method for molding a tire by sequentially winding a strip rubber around the surface of a molding drum having a curved surface corresponding to a tire inner surface shape,
The tire molding method according to claim 1, wherein the strip rubber has a round cross-sectional shape.   The tire molding method according to claim 1, wherein the adjacent strip rubbers are wound while being overlapped with each other.   The tire molding method according to claim 1 or 2, wherein the strip rubber is wound to mold a side portion of the tire.   The tire molding method according to claim 3, wherein the side portion includes a rim strip. A tire molding apparatus comprising a molding drum having a curved surface corresponding to a tire inner surface shape and an extruder for extruding a strip rubber from a die, and molding the tire by sequentially winding the strip rubber around the surface of the molding drum,
A tire molding apparatus, wherein the base includes a discharge port through which a strip rubber having a round cross-sectional shape can be extruded.

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