JPS6211666B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for forming a cylindrical member, and more particularly to an improvement in a drum apparatus used for forming green tires in the process of forming vehicle tires.

In the production of vehicle tires, green tires, or unvulcanized tires, are generally produced by wrapping several carcass plies around a cylindrical forming drum, and plying down (downward) the ends of the carcass plies that extend from both ends of the forming drum. The formed green is then formed by placing a bead on the carcass ply near the side edge of the forming drum and then turning up the plyed-down carcass ply end. The tire is then removed from the forming drum.

In the molding of such green tires, a segmented molding drum whose overall diameter can be reduced has been used in order to facilitate the removal of the green tire from the molding drum. This split molding drum is of a type in which, when the green tire is removed from the molding drum, the circumferential parts divided into a plurality of parts each move radially inward to substantially reduce the diameter of the molding drum.

One of these split molding drums was
There is a device described in Publication No. 25580. This prior art device has a versatile actuation mechanism that can be attached to any type of molding device body. However, this conventional device has the following drawbacks. That is, the alternating arcuate segments of long circumference and arcuate segments of short circumference are each supported by one support member whose radial movement is guided, and thus each arcuate segment is radially outward movement is limited at one point by one stopper means;
The elastic means acting on each support member and forcing it toward the center of the cylinder or drum constituted by the arcuate segments is located at a position offset from the axis of each support member and exerts an eccentric force. The support member is unstable and prone to tilting due to the fact that the end portion of the support member is on a tapered surface in the expanded position of the drum where radial outward movement of the support member is restricted. Due to this inclination, the cylindrical body that the arcuate segments constitute, that is, the drum, takes on the shape of a truncated cone, and as a result, the circumference of the green tire formed by this becomes uneven, which hinders the formation of the desired tire. This will happen.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to eliminate the drawbacks of the conventional apparatus described above, and to provide a molding apparatus that maintains a constant outer circumference of a cylindrical body constituted by arcuate segments and enables high-precision tire molding. It's about doing.

In the present invention, each arcuate segment is supported by a pair of support members, each support member is provided with a guide means and a stopper means, and furthermore, a spring means is disposed between the pair of support members, thereby preventing the support member from tilting. It is characterized by preventing this from occurring.

The features of the invention will become clearer from the following description of the illustrated embodiments.

As shown in FIGS. 1 and 2, a cylindrical member forming apparatus 1
0 includes a cylindrical body 13 formed by alternately arranging arcuate segments 11 having a relatively long circumference and arcuate segments 12 having a relatively short circumference.

Inside each arcuate segment 11, 12 is a plate-shaped portion 11 fixed to the arcuate segment.
a, 12a, a pair of support members 14a, 14b and 15a, 1, respectively, spaced apart in the axial direction of the cylindrical body 13 and extending in the radial direction thereof.
5b is attached. Each support member is slidable in the radial direction within a guide portion 17 consisting of a pair of U-shaped members supported by a cylindrical holding member 16 and a presser plate 16a attached to the holding member, which will be described later. has been done. The holding member 16 is fixed by bolts (not shown) to a flange 21 of a shaft 20 coaxially attached to the main shaft 18 that supports the molding device 10.

Between the holding member 16 and the shaft 20, the shaft 2
Tapered portions 23a, 23b and 24a, 24 which are slidable on the 0 surface and which form a pair on the outer peripheral surface, respectively.
An annular member 25 having b is arranged. A pair of first members spaced apart in the axial direction of the annular member
The tapered portions 23a and 23b respectively define a rolling path in which a pair of support members 14a and 14b for the arcuate segment 11 having a long circumference abut against rollers 26 provided at their ends, and the rolling path is Cylindrical body 10
slopes having constant and mutually equal inclination angles with respect to the central axis of and the following horizontal surfaces 23a', 2
3b'. Similarly, the second tapered portions 24a and 24b, which are spaced apart in the axial direction of the annular member 25, form a pair of support members 15 for the arcuate segments 12 having a short circumference, respectively.
a and 15b define a rolling path that comes into contact with a roller 27 provided at its end, and the rolling path has an equal inclination angle to each other, but the tapered portions 23a and 23b described above
It is formed by a slope whose inclination angle is larger than that of the slope, and horizontal surfaces 24a' and 24b' following the slope.

Each arcuate segment 11, 12 has a pair of coil springs 28 arranged at approximately equal intervals between the pair of support members 14a, 14b and 15a, 15b.
As a result, a force biasing the cylindrical body 13 inward in the radial direction is constantly applied. One end of the coil spring 28 is hooked to the plate portions 11a, 12a, and the other end is hooked to a mounting ring 29 fixed to the holding member 16.

The annular member 25 includes a spring assembly consisting of a coil spring disposed in a stepped bore extending through the tapered portion 23b and a guide rod 31 disposed within the bore and within the spring. One end of the guide rod 31 is fixed to the flange 18a of the main shaft 18, and the other end is in contact with the annular member 25. There is a shaft 2 between the tapered parts 24a and 24b.
The key 3 that engages with the key groove 32 provided in the
3 is provided. The annular member 25 uses the cylindrical holding member 16 as a cylinder part, and the cylinder chamber 3
4 is a piston part slidably housed in the spring assembly 4, and the piston part is supplied to the cylinder chamber 34 through a pressurized fluid supply/discharge hole 35 provided in the end wall of the holding member 16. It moves to the right in FIG. 2 against the biasing force of the three-dimensional object, and due to the action of the spring assembly, the pressurized fluid is discharged from the cylinder chamber 34 through the pressurized fluid supply/discharge hole 35. Able to move entirely to the left.

Next, to explain the operation of the forming device 10, the cylindrical body 13 has completed expansion in the state shown in FIGS. 1 and 2, and the rollers 2 provided at the ends of each support member
6 and 27 are horizontal surfaces 23a' and 2 of the tapered part, respectively.
3b', 24a', and 24b' and are in a stable resting state. Moreover, the projections 36 provided on each support member engage with the stopper pieces 37 provided on the annular member, thereby preventing the support members from moving outward in the radial direction. In addition, the coil spring 28
In the tension state, a force is applied to each arcuate member to draw it inward in the radial direction.
Furthermore, the coil spring 30 is in a compressed state,
The annular body 25 is maintained in the illustrated position in equilibrium with the fluid pressure introduced into the cylinder chamber 34.

As the pressurized fluid in the cylinder chamber 34 is discharged, the annular member 25 is entirely moved to the left by the action of the coil spring 30. During this time, the contact surfaces of the tapered portions with respect to the rollers 26, 27 at the ends of each support member change from horizontal surfaces to sloped surfaces, and the tapered portions 24a, 24
The inclination angle of the slope 4b is different from that of the other tapered parts 23a and 23.
b is larger than the slope of the arcuate segment 12 and its support member 15 during movement of the annular member 25.
a, 15b move radially inwardly more than arcuate segment 11 and its support members 14a, 14b. As a result, as shown in FIG. 3, the radius of the cylindrical body 13 changes from the expanded position (the maximum diameter of the cylindrical body) shown by the broken line to the contracted position (the minimum diameter of the cylindrical body) shown by the solid line.

When the annular member 25 has moved completely to the left in FIG.
Due to the action of 0, the cylinder chamber 34 remains stably stationary unless a fluid pressure opposing this is introduced into the cylinder chamber 34.

When fluid pressure is supplied to the cylinder chamber again, the annular member 25 moves to the coil spring 3, contrary to what has been described above.
During this movement, the support members 14a-15b, together with the arcuate segments 11, 12, move radially outward toward the position shown in FIG. 2 against an acting force of 0.

The maximum diameter of the cylindrical body 13 formed by the arcuate segments is obtained when the annular member 25 is at the rightmost position in the cylinder chamber, and the minimum diameter is obtained when the annular member 25 is at the leftmost position in the cylinder chamber. By fixing the annular member at an arbitrary position in the cylinder chamber, the desired diameter of the cylindrical body 13 can be obtained. The carcass ply consists of cylindrical body 1
3 is wound while the cylinder occupies a diameter smaller than its maximum diameter, and while the cylinder occupies its maximum diameter, the carcass ply is held under tension and its ends are turned up to form a green tire. The molded green tire can be removed by reducing the diameter of the cylindrical body 13.

According to the invention, each arcuate segment is always supported by a pair of support members, the ends of each support member being located on the horizontal plane of the tapered part while the cylinder has a maximum diameter and each support The stopper means provided for each member acts to prevent the support member from tilting, and the spring means provided between the support member and its holding member is located approximately at the longitudinal center of each arcuate member. By eliminating tilting due to the spring force, the arcuate segment and its support member can ensure a stable, tilt-free radial movement and stationary state.

Therefore, the prevention of inclination of the arcuate segments does not cause a difference in the circumferential length of the cylindrical member as a molded body, and the cylindrical member can be molded with high precision.

[Brief explanation of the drawing]

1 is a partial side view of the forming apparatus of the present invention in an expanded position in which each arcuate segment forms a complete cylinder; FIG. 2 is a sectional view taken along the line - of FIG. 1; 3 is a partial side view similar to FIG. 1, with each arcuate segment in a position to form a cylinder of minimum diameter; FIG. 10: Molding device, 11: Arc-shaped segment with long circumference, 12: Arc-shaped segment with short circumference, 13:
Cylindrical body, 17: Guide portion, 14a, 14b: First support member, 15a, 15b: Second support member, 1
6: Holding member (cylinder part), 23a, 23b:
1st taper part, 24a, 24b: 2nd taper part, 25: Annular member (piston part), 26, 2
7: Roller, 30: Coil spring, 34: Cylinder chamber, 35: Pressurized fluid supply/discharge hole, 36: Projection,
37: Stopper piece.

Claims (1)

[Claims] 1 A cylindrical body formed by alternately arranging arcuate segments with long circumferences and arcuate segments with short circumferences, and a pair of support members supporting each of the arcuate segments and spaced apart in the axial direction of the cylindrical body. a pair of support members each extending in the radial direction of the cylindrical body with one end fixed to the arcuate segment and each supporting member abutting the pair of support members for each long circumference arcuate segment having a horizontal surface and A pair of first tapered portions each having a slope following the first taper portion and abutting the other end of the pair of support members for each arcuate segment having a short circumference, each having a horizontal surface and a slope following the first taper portion, and each having an inclined slope. is provided with a pair of second tapered portions having a slope larger than the slope of the first tapered portion and is movable along the central axis of the cylindrical body, and one end located between each pair of support members; a spring means whose other end is locked to the arc-shaped member and whose other end is locked to the annular member, a cylinder chamber provided within the cylindrical body and housing the annular member as a piston portion, and supplying pressurized fluid to the cylinder chamber. , a means for discharging;
a guide member provided on the annular member for each support member to guide the radial movement of the cylindrical body made by the support member on the tapered portion as the piston portion moves within the cylinder chamber; , stopper means provided for each support member to limit radially outward movement of the support member when the other end of the support member is on the horizontal plane of the tapered portion. .