JPH0241407B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tire building drum, and more particularly to an improvement in a forming drum in a second stage forming apparatus for radial tires.

In general, the tire molding drum of the second stage molding device used when molding radial green tires in two stages, the first and second stage, is used for the tire molding drum that is transferred to the outer periphery of the tire molding drum in the second stage molding process. While the first stage green tire is shaped into a toroidal shape, a belt/tread annular body is integrally joined to the outer periphery of the toroidally shaped green tire to form a second stage green tire. It is configured as follows.

In order to improve the productivity of the tires mentioned above, the important points regarding the structure of the tire forming drum are: (1) The bead seats that hold the bead of the green tire during the forming process are aligned in the radial direction of the forming drum. (2) When shaping a cylindrical first-stage green tire into a toroidal shape, the inner surface of the green tire is directly shaped without using a rubber bladder for shaving that covers the entire inner surface of the green tire. (3) In relation to points (1) and (2) above, regardless of whether the tire has a different cross-sectional width at the bead or a tire of any aspect ratio, The bead part can be easily fixed in the correct position on the bead seat, and it does not move during shaping, furthermore, the shaping air can be easily sealed, and the structure is simple.

In other words, as described in (1), by configuring the bead seat so that it can expand and contract in the radial direction of the forming drum, it is possible to install an automatic attachment/detachment device for each green tire in the first and second stages, and to install a belt/tread ring. This makes it easier to install an automatic transfer device, and it also makes it easier to set the optimal bead seat outer diameter by adapting it to tires with different inner diameters of the bead, and as mentioned in (2), it does not use a rubber bladder. This eliminates the problems associated with shaping through the rubber bladder, such as close contact between the rubber bladder and the green tire, exhaust time for shaping air inside the rubber bladder, and adverse effects on tire quality due to changes in the rubber bladder wall thickness. By satisfying the points described above, productivity and quality can be further improved.

However, the current situation is that a tire forming drum that satisfies all of the above-mentioned points and has a simple structure has not yet been developed.

The present invention was developed as a result of studies to solve the above-mentioned problems.

Therefore, an object of the present invention is to provide an excellent tire forming drum that satisfies all of the above-mentioned points.

That is, the present invention involves forming a cylindrical first-stage green tire into a toroidal shape, and integrally joining a belt/tread annular body around the outer periphery of the toroidal-shaped green tire to form a second-stage green tire. In the tire building drum, a bead seat mounting member is provided on an inner shaft and an outer shaft that are accessible along the axis of the tire building drum, and is divided into a plurality of segments in the circumferential direction of the drum and is expandable and contractible in the radial direction. At the same time, a bead seat is attached to each bead seat mounting member so that the bead portion gripping surfaces face each other, and the bead seat is pressed in the diametrical direction between the bead seat mounting members and cooperated with each bead seat. The present invention is characterized in that a pair of bladders for gripping the bead portion is disposed, and a diameter expansion adjusting means for adjusting the diameter expansion of the bead seat is installed on the bead seat mounting member.

Hereinafter, the present invention will be explained in detail by way of examples with reference to the drawings.

FIG. 1 is a front cross-sectional explanatory view showing the main parts of a tire forming drum according to an embodiment of the present invention, and FIG. 2 is a partially enlarged perspective view showing a state in which a bead seat is attached to the same bead seat mounting member. .

In the figure, E is a tire forming drum according to an embodiment of the present invention, which shapes a cylindrical first-stage green tire into a toroidal shape, and a belt/tread annular body on the outer periphery of this toroidally shaped green tire. The structure is such that a second stage green tire can be formed by integrally joining the two. The present invention particularly provides a bead seat mounting member 1 which is divided into a plurality of segments in the circumferential direction and is expandable and contractible in the radial direction near each outer end of the inner shaft 1 and the outer shaft 2.
0, 10', and the bead seats 20, 20' formed in a substantially L-shape on the free end side of each bead seat mounting member 10, 10' are attached to the opening side 20a,
20a' are mounted so as to face each other, and positioned between the bead seat mounting member 10 on the inner shaft 1 side and the bead seat mounting member 10' on the outer shaft 2 side,
When the inner shaft 1 and the outer shaft 2 are inflated, each of the bead seats 20, 20' is pressed in the direction of radial expansion, and the bead portion B of the green tire T is clamped between each of the bead seats 20, 20'. A pair of left and right bladders 30, 30' formed to have the same shape as shown in FIG.

This structure will be further explained. First, to explain the bead seat mounting members 10 and 10', the bead seat mounting member 10 attached to the inner shaft 1,
Since the bead seat mounting member 10' attached to the outer shaft has the same structure, the bead seat mounting member 10' attached to the inner shaft 1 will be explained here, and each of the bead seat mounting members 10' on the outer shaft 2 side will be explained. For component parts, mark the numbers shown in the figure with a dash.

The bead seat mounting member 10 has an outer flange 11 attached to the inner shaft and a bracket 11b projecting from the outer periphery of the flange portion 11a of the outer flange 11 at intervals.
The arm 12 is pivoted by a pin 11c so as to be expandable and contractible in the radial direction, and the sliding surface 11d of the outer flange 11
It is composed of a sliding member 13 that is slidably provided on the arm 12, and a link 14 that connects the upper part of the sliding member 13 and the free end side of the arm 12. The bead seat 20 mentioned above
is installed.

Further, 15 is a rod, and the outer flange 11
As shown in the figure, a spring 16 is provided on the inner side of the flange portion 11a of the flange portion 11a and is provided at intervals in the circumferential direction. The arm 12 is constantly urged in the direction of diameter reduction by the elastic force of the arm 16. Although this structure is not shown on the bead seat mounting member 10' on the outer shaft 2 side in FIG. 1 due to the fact that the cut planes are different, it is natural that they have the same structure.

Further, the sliding members 13, 13' are provided with adjustment screws 17 (not shown), 17' projecting at required positions so as to pass through the outer flanges 11, 11', as shown on the right side of FIG. This adjustment screw 1
7, 17' screws 18 (not shown), 1
8' in an appropriate direction to adjust the screwing position, the bead seat mounting members 10, 10'
The enlarged diameter position of the bead seats 20, 20' can be appropriately set via the .

Next, as shown in FIG. 2, the bead seats 20, 20' described above have elongated flanges 21, 21' formed in a substantially L shape and extending radially outward, and the bead seats of the green tire T. Surface 22, 2 supporting part B
2' and the surface 2 where the bladders 30, 30' contact.
3 and 23' are integrally constructed and are fixed to the respective free ends of the arms 12 and 12' of the bead seat mounting members 10 and 10'. The gap between the adjacent bead seats 20, 20' is set to be minimized when the diameter is reduced.

In this embodiment, since the bead seats 20, 20' are configured as described above, the bladder 3
0, 30' are expanded by compressed air, the bead seats 20, 30' are expanded by the bladders 30, 30'.
20' operates in the diameter expanding direction to grip the bead portion B of the green tire T, and the bladder 30,
30' can force the bead part B onto the elongated flanges 21, 21' from the inside in the axial direction.

The above-mentioned bladders 30, 30' are located inside each of the above-mentioned bead seat mounting members 10, 10', and are attached to the bladder clamp rings 31, 31' attached to the inner shaft 1 and the outer shaft 2, respectively. It is removably fixed to the outer peripheral edge via outer rings 32, 32' and inner rings 33, 33', and rings 34, 34 supporting each bladder 30, 30' are attached to each inner ring 33, 33'. ' is attached. and the bladder 30,3
0', a part of which is located radially inward of the bead seats 20, 20', and the remaining part is located inside the bead seats 20, 20'.
It is arranged so as to be axially inward than the axially inner end of 0'.

Further, the inner shaft 1 includes the bladders 30, 3.
A compressed air passage 3 for inflation of 0' and a compressed air passage 4 for shaping green tires T are provided. The compressed air for inflation of the bladders 30, 30' passes through the passage 3 and through the air passages 35, 35' provided in the bladder clamp rings 31, 31'.
It is delivered into said bladder 30, 30'.

In addition, in the figure, 5 and 6 are nuts, respectively, and the nut 5 is a nut for attaching the bead seat attachment member 10 and the bladder clamp ring 31 to the inner shaft 1, and the nut 6 is a nut for attaching the bead seat attachment member 10 and the bladder clamp ring 31 to the inner shaft 1.
This is a nut for attaching the bladder clamp ring 31' and the bladder clamp ring 31' to the outer shaft 2.

Next, the operation of the tire forming drum described above will be explained.

First, with the diameters of the bead seats 20 and 20' reduced, the distance between the left and right bead seats is set to be slightly wider than the side width of the bead of the cylindrical first stage green tire, and the green tire is inserted into the automatic insertion device (not shown). (not included).

The distance D between the outer surface of the bead portion B shown on the right side of FIG. 1 and the elongated flange 21' is set to the maximum value of the error based on the stopping accuracy of the automatic green tire insertion device and the green tire gripping position accuracy of the device. I'll keep it.

Next, when compressed air is supplied into the bladders 30, 30' through the compressed air passage 3 in the inner shaft 1 and the compressed air passages 35, 35' in the bladder clamp rings 31, 31', the bladder 30,
30' expands and pushes up the bead seats 20, 20' in the diametrical direction to expand the diameter. Bead seat 20, 20'
is stopped at the appropriate outer diameter by adjusting screws 18, 18', and bladders 30, 30' are further expanded. In this way, the bead portion B is
0' and bladders 30, 30'.

Next, when the green tire automatic insertion device (not shown) separates from the main drum E, the inner shaft 1 and the outer shaft 2 are moved axially inwardly, and the bead seats 20, 20'
At the same time, compressed air is supplied through the compressed air passage 4 in the inner shaft 1 to shape the green tire T into a toroidal shape.

At the beginning of this shaping, the bead portion B is held between the bladders 30, 30' and the elongated flanges 21, 21', and from then on, the bladders are pressed against each other with a force equal to or more than the force with which the bead portion B attempts to move until the shaping is completed. If the internal pressures 30 and 30' are set, the bead portion B will not move. Furthermore, since the bladders 30, 30' and the bead portion B are in close contact with each other, shaping air will not leak.
The left side of FIG. 1 shows the green tire T shaped into a toroidal shape.

Next, a belt tread annular body (not shown) formed by another device is transferred by a transfer device (not shown) onto the green tire T shaped into a toroidal shape, and is brought into close contact with the green tire T. The second step is a green tire, that is, a completely green tire. Note that this step is based on a known method, and detailed description thereof will be omitted here.

Next, a finished green tire take-out device (not shown) grips the finished green tire outwardly, and the bladder 3
0.0, 30' compressed air and green tire shaping compressed air are exhausted, and the bead seats 20, 20' are reduced in diameter by the force of the springs 16, 16'.

Next, when the finished green tire is removed by a finished green tire removal device (not shown), the drum E returns to its initial state and waits for the next green tire to be inserted.

As described above, the present invention provides a bead seat mounting member that is divided into a plurality of segments in the circumferential direction of the drum and that has an inner shaft and an outer shaft that can be approached along the axis of the tire building drum, and that is expandable and contractible in the radial direction. At the same time, a bead seat is attached to each bead seat mounting member so that the bead portion gripping surfaces face each other, and the bead seat is pressed in the diametrical direction between the bead mounting members and in cooperation with each bead seat. Since a pair of bladders for gripping the bead portion are provided, and a diameter expansion adjusting means for adjusting the diameter expansion of the bead seat is installed on the bead seat mounting member, the following effects are achieved.
That is, since the outer diameter of the bead seat can be easily adjusted, it is possible to immediately adapt to the molding of tires with different inner diameters of the bead portion. In addition, it becomes easier to install automatic green tire attachment/detachment equipment, belt/tread annular body transfer equipment, etc., and automation becomes possible.

It can also be applied to tires with different bead widths. Additionally, when installing green tires, it is possible to deal with misalignment of the green tires. Furthermore, the bead portion of tires of any aspect ratio can be fixed.

There is no need to shave the green tire through a shaving bladder. Therefore, it is not necessary to prevent the surface of the green tire shaving bladder from coming into close contact with the inner surface of the green tire. Furthermore, since the shaving air is exhausted quickly after the molding is completed, the molding time can be shortened. Furthermore, deterioration in tire quality caused by uneven wall thickness of the shaving bladder can be prevented.

[Brief explanation of drawings]

FIG. 1 is a front cross-sectional explanatory view showing the main parts of a tire forming drum according to an embodiment of the present invention, and FIG. 2 is a partially enlarged perspective view showing a state in which a bead seat is attached to the same bead seat mounting member. . 1... Inner shaft, 2... Outer shaft, 10, 10'... Bead seat mounting member, 20, 20'... Bead seat, 2
0a, 20'a...Opening of bead seat, 30, 3
0'... Bladder, T... Raw tire, B... Bead part of raw tire.

Claims (1)

[Claims] 1 A cylindrical first-stage green tire is formed into a toroidal shape, and a belt/tread annular body is integrally joined to the outer periphery of the toroidal-shaped green tire to form a second stage green tire.
In a tire forming drum configured to form a staged green tire, the drum is divided into a plurality of segments in the circumferential direction into an inner shaft and an outer shaft that can be approached along the axis of the tire forming drum, and expands and contracts in the radial direction. Attaching flexible bead seat mounting members, respectively, mounting a bead seat to each bead seat mounting member so that the bead portion gripping surfaces face each other, and pressing the bead seat in the diametrically expanding direction between the bead seat mounting members. Tire molding characterized in that a pair of bladders are arranged to grip the bead portion in cooperation with each bead seat, and a diameter expansion adjustment means for adjusting the diameter expansion of the bead seat is installed on the bead seat mounting member. drum.