JP6972771B2 - Molding drum and rubber member molding method using it - Google Patents

Description

The present invention relates to a molding drum and a method for molding a rubber member using the molding drum.

In recent years, for example, as a method for manufacturing a pneumatic tire or a rubber member thereof, an unvulcanized ribbon-shaped rubber strip is wound on an outer peripheral surface of a molding drum to form the rubber member, and then the rubber member is molded by the molding drum. Is being removed from.

In such a manufacturing method, in order to make it easy to remove the rubber member from the molding drum, it is effective to reduce the adhesiveness between the rubber member and the molding drum. Therefore, for example, it has been proposed to increase the surface roughness of the outer peripheral surface of the molded drum.

Japanese Unexamined Patent Publication No. 2002-172709

However, the molded drum having the outer peripheral surface having a large surface roughness as described above is said to have low productivity when the rubber strip is wound, in particular, the winding start end of the rubber strip falls off from the outer peripheral surface. There was a problem.

The present invention has been devised in view of the above circumstances, and is based on improving the outer peripheral surface of the molded drum, and can increase the productivity of the rubber member. Molding of the molded drum and the molding of the rubber member using the same. Its main purpose is to provide a method.

The present invention is a molding drum for spirally winding an unvulcanized and ribbon-shaped rubber strip around an outer peripheral surface to form a rubber member, and the outer peripheral surface is attached to the winding start end of the rubber strip. The surface roughness of the first region includes a first region to be formed and a second region adjacent to the first region and to which the rubber strip is attached except for the winding start end of the rubber strip. It is smaller than the surface roughness of the second region.

In the molded drum according to the present invention, it is desirable that the first region has a width of 100 to 500 mm in the drum axial direction.

The molded drum according to the present invention preferably has an arithmetic mean roughness of the first region of 1.5 to 2.5 μm.

It is desirable that the molded drum according to the present invention includes a suction means in which the outer peripheral surface is provided with a plurality of holes and the rubber strip is sucked through the holes.

It is desirable that the molded drum according to the present invention has a detector on the outer peripheral surface for detecting the state in which the rubber strip is attached.

The present invention is a method for molding a rubber member in which an unvulcanized and ribbon-shaped rubber strip is spirally wound around an outer peripheral surface of a molding drum to form a rubber member, wherein the outer peripheral surface has a small surface roughness. The rubber strip is attached to the first sticking step of sticking the winding start end of the rubber strip to one region, and to the second region adjacent to the first region and having a surface roughness larger than that of the first region. The second pasting step of pasting is included.

In the molding drum of the present invention, the winding start end of the rubber strip can be reliably attached to the first region having a relatively small surface roughness. Further, in the molded drum of the present invention, the rubber member can be easily peeled off from the second region having a large surface roughness after the winding of the rubber member is completed. Therefore, the molded drum of the present invention can improve the productivity of the rubber member.

It is a schematic perspective view of one Example of the molded drum of this invention. It is a front view of the molding drum of FIG. (A) and (b) are cross-sectional views of a forming drum when a rubber strip is wound.

FIG. 1 is a schematic perspective view of the molded drum 1 of the present embodiment (hereinafter, may be simply referred to as “drum 1”). As shown in FIG. 1, the drum 1 of the present embodiment is for winding an unvulcanized and ribbon-shaped rubber strip 30 to form a cylindrical rubber member 31. The rubber member 31 is used, for example, as a constituent material of a pneumatic tire. In the present embodiment, the rubber member 31 is removed from the drum 1 and bonded to other components of a pneumatic tire to form a raw tire (not shown).

The rubber strip 30 preferably has a Mooney viscosity of, for example, 50 ML (1 + 4) 100 ° C. or higher, and preferably 60 ML (1 + 4) 100 ° C. or lower. "Mooney viscosity" is a value measured according to the measurement method described in JIS K 6300-1: 2001 "Unvulcanized rubber-Physical characteristics-Part 1: How to obtain viscosity and scorch time by Mooney viscometer". ..

The rubber strip 30 is not particularly limited, but in order to form a desired cross-sectional shape, it is desirable that the rubber strip 30 has a width w of 10 to 30 mm and a thickness t of about 0.5 to 3.0 mm, for example. ..

In the present embodiment, the drum 1 includes a central shaft 2 and a drum main body 3.

The central shaft 2 is rotatably supported by, for example, a support device having a well-known structure (not shown). The central shaft 2 of the present embodiment is cantilevered by the support device on one side in the drum axis direction.

The drum main body 3 is arranged, for example, outward in the radial direction of the central axis 2 and is rotatably held together with the central axis 2. The drum main body 3 has an outer peripheral surface 4 around which the rubber strip 30 is wound.

The drum main body 3 is formed of, for example, a plurality of segments 5. Each segment 5 of the present embodiment is supported by the scaling means 6 (shown in FIG. 2) on the central axis 2 so that the diameter can be scaled in the radial direction. Due to the reduced diameter of the segment 5, the rubber member 31 is removed from the outer peripheral surface 4.

Each segment 5 is curved in a cross section, for example, in an arc shape. By arranging the segments 5 adjacent to each other in a cylindrical shape, a cylindrical outer peripheral surface 4 is formed.

FIG. 2 is a schematic plan view of the drum 1. As shown in FIG. 2, the outer peripheral surface 4 includes a first region 7 and a second region 8 adjacent to the first region 7.

The winding start end 30a (shown in FIG. 3) of the rubber strip 30 is wound around the first region 7. A winding start end 30a (shown in FIG. 3) and a rubber strip 30 extending from the winding start end 30a are wound around the first region 7 of the present embodiment. The rubber strip 30 excluding the winding start end 30a is wound around the second region 8. The surface roughness of the first region 7 is formed to be smaller than the surface roughness of the second region 8. As a result, the winding start end 30a of the rubber strip 30 can be reliably adhered in the first region 7 having a relatively small surface roughness. Further, since the surface roughness of the second region 8 is relatively large, the rubber member 31 can be easily peeled off from the outer peripheral surface 4 after the winding of the rubber member 31 is completed. Therefore, the drum 1 of the present embodiment can improve the productivity of the rubber member 31. In FIG. 2, the rubber strip 30 in the middle of winding is shown by a virtual line.

The surface roughness of the first region 7 is preferably, for example, 1.5 to 2.5 μm. If the surface roughness of the first region 7 is less than 1.5 μm, the adhesiveness becomes excessively large, and the rubber member 31, particularly the vicinity of the winding start end 30a of the rubber strip 30, may be difficult to remove from the outer peripheral surface 4. .. If the surface roughness of the first region 7 exceeds 2.5 μm, the adhesiveness with the rubber strip 30 may decrease, and the vicinity of the winding start end 30a may fall off. In the present specification, the surface roughness means the arithmetic mean roughness Ra defined in JIS B0601-2001.

In the present embodiment, the first region 7 is formed substantially continuously on the circumference of the drum 1. As a result, the winding start end 30a of the rubber strip 30 can be reliably attached at any position in the circumferential direction of the drum.

In the present embodiment, the first region 7 is provided at two locations on both sides in the drum axial direction with the drum equator Ci interposed therebetween. Thereby, for example, by using the two rubber strips 30 and 30, the rubber member 31 can be formed from both the first regions 7 and 7. The drum equator Ci refers to an intermediate position of the drum main body 3 in the drum axial direction. In the present embodiment, the first region 7 is provided at a position reserved inward in the drum axial direction from the outer end 3e of the drum main body 3 in the drum axial direction.

The outer edge 7e of the first region 7 in the drum axial direction is arranged in a range of, for example, 20% to 40% of the width W of the drum 1 in the drum axial direction from the drum equator Ci.

The width Wa of the first region 7 is determined in relation to the width w and the viscosity of the rubber strip 30. That is, from the viewpoint that the winding start end 30a of the rubber strip 30 is securely attached to the first region 7 and the rubber member 31 is smoothly removed after the rubber strip 30 is attached, the width Wa of the first region 7 is set. It is determined. In the case of the rubber strip 30 described above, it is desirable that the width Wa of the first region 7 in the drum axial direction is 100 to 500 mm.

In the present embodiment, the second region 8 is a central second region 8A arranged between the first regions 7 and 7, and a pair of outer second regions 8B arranged outside the drum axis of the first region 7. It has 8B. As a result, the rubber member 31 can be easily peeled off. The aspect of the second region 8 is not limited to such a mode.

The surface roughness (arithmetic mean roughness) of the second region 8 is not particularly limited, but is preferably larger than 2.5 μm, more preferably 5.0 μm or more, for example. In order to suppress the misalignment of the rubber strip 30 in the second region 8, the surface roughness of the second region 8 is preferably 10 μm or less.

A plurality of holes 10 are provided on the outer peripheral surface 4 of the drum main body 3. In this embodiment, each hole 10 is connected to a suction means (not shown) for sucking the rubber strip 30. As a result, the rubber strip 30 is adsorbed by the suction means through the holes 10, so that the rubber strip 30 is securely attached to the outer peripheral surface 4 and is prevented from falling off or being displaced. As the suction means, for example, a vacuum device having a well-known structure is used, and the suction means is arranged inside the hole 10 in the radial direction of the drum.

In this embodiment, a plurality of holes 10 are provided in each of the first region 7 and the second region 8. As a result, the suction effect of the rubber strip 30 is enhanced on the entire outer peripheral surface 4. The hole 10 may be provided only in the first region 7 or only in the second region 8 where the rubber strip 30 is likely to fall off, for example, in order to facilitate the attachment of only the winding start end 30a. May be done.

In the present embodiment, the holes 10 are formed as a plurality of hole rows 10A arranged along the drum circumferential direction line. As a result, the rubber strip 30 wound around the drum circumference can be effectively adsorbed, so that the productivity of the rubber member 31 is greatly improved. A plurality of hole rows 10A are arranged in the drum axis direction on the outer peripheral surface 4 of the present embodiment. In this embodiment, at least one row of holes 10A is provided in each of the first region 7 and the second region 8.

The inner diameter D of the hole 10 is preferably 2.0 to 5.0 mm. When the inner diameter D is smaller than 2.0 mm, the suction force of the hole 10 is small, and the rubber strip 30 may be easily displaced. If the inner diameter D is larger than 5.0 mm, the rubber strip 30 may be excessively strongly adsorbed and the outer surface of the rubber strip 30 may be dented.

The drum 1 of the present embodiment is provided with a detector 11 for detecting the sticking state of the rubber strip 30. It is desirable that the detector 11 can control, for example, to detect the state in which the rubber strip 30 covers the hole 10 and start the suction by the suction means. As such a detector 11, for example, a phototube having a well-known structure, an optical sensor, a load cell for measuring pressure, or the like is preferably adopted.

Further, it is desirable that the detector 11 can detect that the rubber strip 30 is sufficiently attached to the outer peripheral surface 4 and control the suction by the suction means to stop the suction. In the case of a load cell, since the sticking pressure of the rubber strip 30 is measured, it is possible to accurately control the stop of suction by the suction means.

The detector 11 is provided on the outer peripheral surface 4 in the present embodiment. It is desirable that the detector 11 is provided in the vicinity of the hole 10, and for example, at least one is provided for one hole row 10A. In the present embodiment, one detector 11 is provided between the holes 10 and 10 adjacent to each other in the drum circumferential direction of one hole row 10A.

The detector 11 is not limited to such an embodiment, and may be provided in the hole 10, for example.

Next, a method of forming the rubber member 31 using such a drum 1 will be described. 3 (a) and 3 (b) are cross-sectional views orthogonal to the central axis 2 of the drum 1 when the rubber strip 30 is wound around the drum main body 3. In FIGS. 3A and 3B, the adsorption means is omitted. As shown in FIGS. 3A and 3B, the molding method of the rubber member 31 of the present embodiment includes a sticking step of sticking the rubber strip 30 to the outer peripheral surface 4. As for the molding method of the rubber member 31 of the present embodiment, a well-known step is adopted for the steps other than the pasting step, and therefore the description thereof will be omitted.

The pasting step of the present embodiment includes a first sticking step and a second sticking step. In the sticking step, a drum 1 and an applicator 13 having a well-known structure for supplying the rubber strip 30 to the drum 1 are used. In the present embodiment, the applicator 13 includes a sticking roller 14 for sticking the supplied rubber strip 30 to the outer peripheral surface 4.

As shown in FIG. 3A, in the first sticking step, for example, the rubber strip 30 is conveyed onto the first region 7 of the outer peripheral surface 4 by the applicator 13. Next, the winding start end 30a of the rubber strip 30 is attached to the first region 7 by the attachment roller 14 of the applicator 13. Next, the drum main body 3 is rotated by the support device (not shown), and the rubber strip 30 is spirally attached on the first region 7 of the outer peripheral surface 4.

At this time, when the detector 11 detects that the rubber strip 30 is attached so as to cover the hole 10, the suction means starts sucking the rubber strip 30. This ensures that the winding start end 30a, which is particularly easy to fall off, is attached.

Next, in the present embodiment, when the detector 11 confirms that the rubber strip 30 is sufficiently adsorbed, the adsorption by the adsorption means is stopped. In the present embodiment, since one detector 11 is provided in the hole row 10A, it is desirable that the start and stop of suction by the suction means is controlled for each hole row 10A.

Next, the second pasting step is performed. In the second sticking step of the present embodiment, for example, the rubber strip 30 used in the first sticking step is continuously wound around the second region 8. Also in this second sticking step, when the detector 11 detects that the rubber strip 30 is stuck so as to cover the hole 10, suction of the rubber strip 30 stuck by the suction means is started. Further, when the detector 11 confirms that the rubber strip 30 is sufficiently adsorbed, the adsorption by the adsorption means is stopped. As a result, the rubber member 31 is molded with good productivity.

In the first sticking step, it is necessary to stick the winding start end 30a accurately and surely. Further, in the second pasting step, it is required to shorten the winding time of the rubber strip 30 to improve the productivity. Therefore, it is desirable that the peripheral speed V1 of the drum main body 3 in the first sticking step is smaller than the peripheral speed V2 of the drum main body 3 in the second sticking step. In order to further improve productivity, the peripheral speed V1a of the drum main body 3 for one round of the drum 1 is set from the winding start end 30a in the first sticking step, and the peripheral speed V2 of the drum main body 3 in the second sticking step. It is desirable to make it smaller than.

Further, it is desirable that the peripheral speed V of the drum main body 3 is associated with the feeding speed v of the rubber strip 30 of the applicator 13. Considering proper attachment of the rubber strip 30 to the outer peripheral surface 4, for example, the ratio (V / v) of the peripheral speed V of the drum main body 3 to the delivery speed v of the applicator 13 is (100/98) to (100/90) is desirable.

The pasting step is not limited to the above-mentioned embodiment. In the pasting step, for example, the peripheral speed V of the drum main body 3 and the timing of suction may be controlled to be synchronized. That is, as shown in FIG. 3B, the holes 10a not covered by the rubber strip 30 are not adsorbed by the suction means, and the holes 10b covered by the rubber strip 30 are adsorbed by the suction means. .. As a result, the suction is started and stopped for each hole 10, so that the rubber strip 30 can be more effectively attached to the outer peripheral surface 4, and the productivity is improved.

Although the particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the illustrated embodiment and can be modified into various embodiments.

1 Molding drum 4 Outer peripheral surface 31 Rubber member 30 Rubber strip 30a Winding start end 7 1st region 8 2nd region

Claims (7)

A molding drum for forming a rubber member by spirally winding an unvulcanized and ribbon-shaped rubber strip around the outer peripheral surface.
The outer peripheral surface has a first region to which the winding start end of the rubber strip is attached and a second region adjacent to the first region and to which the rubber strip is attached except for the winding start end of the rubber strip. Including and
The surface roughness of the first region is smaller than the surface roughness of the second region.
Includes a central axis, a drum body that is rotatably held together with the central axis, and a support device that rotatably supports the central axis.
In the support device, the peripheral speed of the drum main body when the rubber strip is attached to the first region is smaller than the peripheral speed of the drum main body when the rubber strip is attached to the second region. Has the function of
Molding drum. The molded drum according to claim 1, wherein the first region has a width of 100 to 500 mm in the drum axial direction. The molded drum according to claim 1 or 2, wherein the arithmetic average roughness of the first region is 1.5 to 2.5 μm. The outer peripheral surface is provided with a plurality of holes, and the outer peripheral surface is provided with a plurality of holes.
The molded drum according to any one of claims 1 to 3, further comprising an adsorption means for adsorbing the rubber strip through each of the holes. The molded drum according to any one of claims 1 to 4, wherein the outer peripheral surface has a detector for detecting a sticking state of the rubber strip. A method for forming a rubber member, which is a method of forming a rubber member by spirally winding an unvulcanized and ribbon-shaped rubber strip around the outer peripheral surface of a forming drum.
The first sticking step of sticking the winding start end of the rubber strip to the first region where the surface roughness of the outer peripheral surface is small,
The second sticking step of sticking the rubber strip to the second region adjacent to the first region and having a surface roughness larger than that of the first region is included.
In the first sticking step and the second sticking step, the drum main body of the molded drum is rotated.
The peripheral speed V1 of the drum main body in the first sticking step is smaller than the peripheral speed V2 of the drum main body in the second sticking step.
How to mold a rubber member. In the first sticking step, the peripheral speed V1a of the drum main body portion for one round of the molding drum from the winding start end of the rubber strip is the peripheral speed V2 of the drum main body portion in the second sticking step. The method for molding a rubber member according to claim 6 , which is smaller than the above.

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