JPH0135728B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a tire curing mold.

As a mold for vulcanizing automobile tires, there is an upper mold and a lower mold arranged above and below to mold the carcass part of the tire, and a space between the upper mold and the lower mold to mold the tread part of the tire. It consists of a plurality of circumferential segments arranged in a ring shape, and the circumferential segments are vertically slidably attached to the inner surface of a tapered ring that protrudes from the outer periphery of the upper mold and has a downwardly widening taper. something is known.
An example of this known tire curing mold will be explained with reference to FIGS. 1 and 2. Above the lower mold 1 for molding one carcass part Aa of the tire A,
An upper mold 2 for molding the other carcass portion Aa is provided so as to be movable up and down, and a tapered ring 2a is provided on the outer periphery of the upper mold 2 to protrude downward. The inner surface 2b of this tapered ring 2a has a downwardly widening taper, and a plurality of guide keys 3 in the generatrix direction are attached to this inner surface 2b at equal intervals in the circumferential direction with bolts (not shown). A stop pin 4 is provided near the bottom of the guide key 3 to protrude inward. On the other hand, the tread portion Ab of tire A
The circumferential segment 5 for molding consists of an outer carrier 6 and an inner tread mold 7, the outer surface 6a of which is formed by the inner surface 2b of the tapered ring 2a.
It is formed into a conical surface corresponding to the outer surface 6.
A guide groove 6b cut in the center of the guide groove 6b is slidably fitted into the guide key 3 of the tapered ring 2a, and a locking groove cut in the lower half of the bottom of the guide groove 6b. By engaging the stop pin 4 of the taper ring 2a with the upper end step of the taper ring 6c,
A circumferential segment 5 is suspended from the upper die 2 . Then, attach the green tire B to the lower mold 1, and
When the green tire B is vertically lowered from above, the upper bead portion of the green tire B engages with the upper mold 2 and the green tire B is compressed in the vertical direction. As it comes into contact with the outer circumferential plane part 1a, it is pushed radially inward along the outer circumferential plane part 1a. Note that 8 is a hook fixed to the lower end of the circumferential segment 5, and 1b is a hook hole drilled in the outer circumferential flat portion 1a of the lower mold 1.

However, in the conventional tire curing mold described above, the lower surface of the circumferential segment 5 comes into contact with the outer circumferential flat part 1a of the lower mold 1 and then moves inward, so that the upper mold 2 is lowered. When the green tire B is being compressed in the vertical direction due to As a result, the tread portion Bb is pressed vertically, making it impossible for the tread portion Bb to descend smoothly.As a result, the upper shoulder of the tread portion Ab of the product tire A is formed to be thicker than the lower shoulder, resulting in poor uniformity. The disadvantage was that it caused This defect in UmiFuomi becomes more severe as the height of the protrusion 7a of the tread mold 7 of the circumferential segment 5 is set higher in order to form the tread groove Ac of the tire A deeper. The mold for sulfur has a tread groove Ac
It could not be used for vulcanization molding of tires with a particularly deep depth.

This invention makes it possible to make a simple modification to the tire curing mold described above, so that when the circumferential segment moves inward, the circumferential segment simultaneously moves at the same speed as the tread portion of the green tire. It is designed to descend.

That is, the present invention provides an upper mold and a lower mold disposed vertically for molding the carcass portion of a tire, and a ring-shaped mold disposed between the upper mold and the lower mold for molding the tread portion of the tire. The tire machine is made up of a plurality of circumferential segments, each of which is vertically slidably attached to the inner surface of a tapered ring that protrudes downward from the outer periphery of an upper mold and has a downwardly widening taper. In the sulfur mold, a cam whose inner surface is inclined in a direction opposite to the inner surface of the tapered ring is provided on the upper surface of the outer peripheral part of the lower mold, and a cam with an inner surface of the cam is provided on the lower outer surface of the circumferential segment. As the upper mold descends, the circumferential segment forms a sliding part and is guided by both the inner surface of the tapered ring and the inner surface of the cam, and slopes inward at a speed approximately equal to the descending speed of the tread of the green tire. This is a tire vulcanizing mold characterized in that it descends at 200 degrees.

Embodiments of the present invention will be described below with reference to FIGS. 3 to 5. However, the same parts as in the conventional apparatus shown in FIGS. 1 and 2 are given the same reference numerals, and the explanation thereof will be omitted.

3 and 4, two cam grooves 6d, 6d are located at the lower part of the outer surface 6a of the circumferential segment 5 on both sides of the guide groove 6b, and are inclined in the opposite direction of the guide groove 6b. The cam grooves 6 are cut parallel to each other, and the cam grooves 6 are cut in parallel to each other.
d, 6d, a projecting piece-shaped cam 9 that slidably fits into the
9 is provided in a protruding manner, and the groove bottom of the cam groove 6d is formed to slide along the inner surface 9a of the cam 9.

In the above structure, when the green tire B is attached to the lower mold 1 and the upper mold 2 is lowered vertically, the upper mold 2 is lowered to a predetermined position and the upper bead part is
After engaging with the green tire B, the green tire B is compressed in the vertical direction. On the other hand, the circumferential segment 5 is suspended from the upper mold 2 and lowered as in the conventional case, but after the cam groove 6d is fitted into the cam 9, the inner surface of the cam 9 is moved as shown in FIG. 9a, the circumferential segment 5 reaches the innermost end of its stroke and stops moving at the same time as the taper ring 2a comes into contact with the lower die 1. At this time, by setting the inclination angle α of the inner surface 9a of the cam 9 with respect to the horizontal plane to be equal to the inclination angle β of the inner surface 2b of the tapered ring 2a, the circumferential segment 5 is guided by the cam 9 and descends. When the speed is 1/ of the descending speed of upper mold 2
It can be set to 2. On the other hand, green tire B
After the upper bead portion of the upper mold 2 is engaged with the upper mold 2, the tread portion Bb is lowered at a speed that is half the lowering speed of the upper mold 2. Therefore, the upper bead portion of the green tire B is engaged with the upper mold 1, and the distance between the lower surface of the circumferential segment 5 and the lower mold 1 is equal to the distance between the upper surface of the circumferential segment 5 and the upper mold 2. When the cam 9 is bent, the cam groove 6d of the circumferential segment 5 is inserted into the cam 9.
By setting the shape of the cam 9 so that it fits, the circumferential segment 5 can be lowered at the same speed as the tread portion Bb of the green tire B. However, the protrusion 7a of the tread shape 7 of the circumferential segment 5 is the tread part of the green tire B.
Since the descending speed decreases due to resistance when entering Bb, it is preferable that the inclination angle α of the cam is slightly larger than the inclination angle β of the tapered ring 2a. When raising the upper mold 2 after vulcanization, the bead ring (not shown) of the lower mold 1 with which the lower bead of the tire A is engaged is raised a predetermined distance, and Segment 5 rises in an outwardly inclined manner, and tread type 7 becomes tire A.
It is preferable to release the above-mentioned engagement after separating from the tread portion Ab, and in this case, the conventional hook 8 becomes unnecessary.

In the above embodiment, as shown in FIG.
The height of the cam 9 is lower than that of the above embodiment, and the upper surface is formed wider in the radial direction. ), and then is guided by the inner surface 9a of the cam 9 and can be lowered in an inclined manner (in the direction of arrow P). Also, the seventh
As shown in the figure, the cam 9 may be formed into a ring shape, and the lower outer surface 6e of the circumferential segment 5 may be formed into a tapered surface. Incidentally, the inclination angle α of the inner surface 9a of the cam 9, the height of the cam 9, the timing at which the circumferential segment 5 contacts the cam 9, etc., depend on the rigidity and shape of the green tire B, and the tread groove Ac of the product tire A. It can be changed appropriately depending on the depth, the width of the tread portion Ab, etc. Furthermore, the circumferential segment 5 may be formed integrally with the carrier 6 and the removable tread mold 7, and the guide groove 6c and the cam groove 6d may be formed as separate parts that are removable. Of course, when the groove is formed and worn out, only the groove can be replaced with a new one.

As explained above, in this invention, a cam is provided protruding from the lower die so that the circumferential segments move inward at the same time as they descend. The descending speed of the tread portion and the descending speed of the circumferential segment can be made to match, thereby improving the uniformity of the product tire, and making it possible to easily manufacture tires with deep tread grooves, which were previously impossible to manufacture. Furthermore, the structure is simple, and existing tire manufacturing molds can be easily modified.

[Brief explanation of drawings]

FIG. 1 is a vertical cut front view of a conventional tire manufacturing mold, FIG. 2 is a sectional view taken along the line -- in FIG. 1, FIG. 3 is a vertical cut front view of an embodiment of the present invention, and FIG. Figure 3 is a sectional view taken along the - line, Figure 5 is a vertically cut front view when the taper ring is in contact with the cam, and Figure 6 is a vertical cut front view when the taper ring is in contact with the cam.
The figure is a longitudinal sectional view of the main part of a modification, and FIG. 7 is a longitudinal sectional view of the main part of another modification. A: tire, Aa: carcass part, Ab: tread part, B: green tire, 1: lower mold, 2: upper mold,
2a: Tapered ring, 2b: Inner surface, 5: Circumferential segment, 9: Cam, 9a: Inner surface.

Claims (1)

[Scope of Claims] 1. An upper mold and a lower mold arranged above and below to mold the carcass part of the tire, and a ring-shaped mold between the upper mold and the lower mold to mold the tread part of the tire. A tire consisting of a plurality of circumferential segments arranged so that the circumferential segments are vertically slidably attached to the inner surface of a tapered ring that protrudes downward from the outer periphery of an upper die and has a downwardly widening taper. In the vulcanization mold, a cam whose inner surface is inclined in a direction opposite to the inner surface of the tapered ring is provided on the upper surface of the outer peripheral part of the lower mold, and a cam whose inner surface is inclined in the opposite direction to the inner surface of the tapered ring, and the inner surface of the cam is provided on the lower outer surface of the circumferential segment. As the upper die descends, the circumferential segment is guided by both the inner surface of the taper ring and the inner surface of the cam, and slopes inward at a rate approximately equal to the descending speed of the tread of the green tire. A tire curing mold characterized in that it descends at a high speed. 2. The tire curing mold according to claim 1, wherein the cam is formed in the shape of a projecting piece, and a cam groove in which the cam slides is cut into a lower portion of the outer surface of the circumferential segment. 3. The tire curing mold according to claim 1, wherein the cam is formed in a ring shape, and a tapered sliding surface on which the ring-shaped cam slides is formed at the lower part of the outer surface of the circumferential segment. . 4. The tire curing mold according to any one of claims 1 to 3, wherein the inclination angle of the inner surface of the cam is set to be approximately equal to the inclination angle of the inner surface of the tapered ring.