JP7293041B2 - Tire mold and tire manufacturing method - Google Patents

Description

The present invention relates to tire molds and tires.

Conventionally, for example, a tire mold includes a mold body having a hole in the inner surface forming a molding surface for molding a tire, and a mold piece that is detachable from the mold body and fitted into the hole. (For example, Patent Document 1). The air inside the tire mold is sucked to the outside of the tire mold by forming a gap between the mold body and the hole.

By the way, for example, there are cases where the size of the gap between the mold body and the hole is small, or where the gap cannot be formed between the mold body and the hole. In such a case, for example, gas accumulates around the molding surface of the mold piece, so rubber defects are likely to occur in the portion of the tire molded by the mold piece.

JP-A-6-64068

Therefore, the first object is to provide a tire mold that can suppress the occurrence of rubber defects in the portion of the tire molded by the mold piece.

A second object is to provide a tire in which the occurrence of rubber defects in the portion of the tire molded by the mold piece is suppressed.

A tire mold is a tire mold having a molding surface for molding a tire. and a mold piece having a vent hole opened in the molding surface.

Further, in the tire mold, the mold body has a through-hole that is open to the outer surface and penetrates to the hole so that the mold piece is driven out from the hole by a tool, and the vent hole is: The configuration may be such that the tire mold includes a communicating portion that is arranged away from the through-hole and that communicates the vent hole and the through-hole.

Further, in the tire mold, the mold piece includes an on-off valve that opens and closes the vent hole, and the on-off valve includes a tubular valve seat fixed inside the vent hole and a valve seat that closes the vent hole. A configuration may be provided in which a valve body is movable between a closed position and an open position for opening the vent hole.

Further, in the tire mold, the mold body and the mold piece have thermal expansibility, the mold body has a vent hole opened to the molding surface, and the opening area of the vent hole in the mold piece is The average size of the vent holes may be smaller than the average size of the opening areas of the vent holes in the mold body.

Also, a tire is manufactured by the tire mold described above.

FIG. 1 is a schematic diagram of a tire mold according to one embodiment, showing a mold open state. FIG. 2 is a schematic diagram of the tire mold according to the embodiment, showing a closed state of the mold. FIG. 3 is a cross-sectional view of the essential parts of the tire mold according to the embodiment, showing a closed state of the mold. FIG. 4 is an enlarged cross-sectional view taken along line IV--IV of FIG. FIG. 5 is a cross-sectional view of the same portion as FIG. 4, showing a state in which the mold piece is removed from the mold body. FIG. 6 is a cross-sectional view of an on-off valve. FIG. 7 is a cross-sectional view of essential parts of a tire mold according to another embodiment.

An embodiment of a tire mold and a tire will be described below with reference to FIGS. 1 to 6. FIG. Note that in each drawing (similar to FIG. 7), the dimensional ratio of the drawings and the actual dimensional ratios do not necessarily match, and the dimensional ratios between the drawings do not necessarily match.

As shown in FIG. 1, the tire 10 includes a pair of bead portions 11 (only one is shown in FIG. 1) having beads, and a pair ( 1, only one side wall portion 12 is shown. The tire 10 also includes a tread portion 13 that is connected to the outer end portions of the pair of sidewall portions 12 in the tire radial direction D2.

As shown in FIGS. 1 to 3, a tire vulcanizer 1 is provided with a plurality of tire molds 2 . The plurality of tire molds 2 include a pair of side molds 2a, 2a whose molding surfaces 2d are in contact with the sidewall portion 12 of the tire 10, a plurality of tread molds 2b whose molding surfaces 2d are in contact with the tread portion 13 of the tire 10, and the tire 10. A pair of bead molds 2c, 2c into which the bead portions 11 are fitted.

In each figure, the first direction D1 is the tire width direction D1 parallel to the tire rotation axis that is the center of rotation of the tire 10, and the second direction D2 is the tire radial direction D2 that is the diameter direction of the tire 10. and the third direction D3 is the tire circumferential direction D3, which is the direction around the tire rotation axis. As the directions D1 to D3 in the tire mold 2, the directions (tire width direction D1, tire radial direction D2, tire circumferential direction D3) with respect to the tire 10 molded by the tire vulcanizing apparatus 1 are used.

The pair of side molds 2a, 2a are spaced apart in the tire width direction D1 from the tire 10 set inside the molding chamber 1a. Further, the plurality of tread molds 2b are arranged on the sides of the pair of side molds 2a, 2a, and arranged annularly in parallel along the tire circumferential direction D3 with respect to the tire 10 set inside the molding chamber 1a. It is

The tire vulcanizer 1 includes a side base 1b that supports the outside of the side mold 2a, and a tread base 1c that supports the outside of the tread mold 2b. The tire vulcanizer 1 also includes a first moving mechanism 1d for moving the tread mold 2b and the tread base 1c in the tire radial direction D2, the tread mold 2b and the tread base 1c, and the upper side mold 2a and the side base 1b. and a second moving mechanism (not shown) for moving up and down.

Each moving mechanism 1d allows one side mold 2a to contact and separate from the other side mold 2a in the tire width direction D1. It is possible to contact and separate in the radial direction D2. As a result, the plurality of molds 2 have a mold opening position for inserting and removing the tire 10 as shown in FIG. 1 and a mold closing position for molding the tire 10 as shown in FIGS. It is possible to move between

In the tire vulcanizing apparatus 1, when the mold is opened as shown in FIG. 1, the side mold 2a and the tread mold 2b are separated, so that the tire 10 can be put in and taken out. In the tire vulcanizing apparatus 1, the side mold 2a and the tread mold 2b are in press contact with each other when the mold is closed as shown in FIGS. A certain molding chamber 1a is formed inside.

The side mold 2a includes a mold body 3 and a mold piece 4 that is detachable from the mold body 3. As shown in FIG. As shown in FIGS. 4 and 5, the mold body 3 has a hole portion 3b in an inner surface portion 3a forming the molding surface 2d, and the mold piece 4 is fitted in the hole portion 3b.

The mold main body 3 forms a molding surface 2d with a part of the inner surface portion 3a, and the mold piece 4 forms the molding surface 2d with the entire inner surface portion 4b. In addition, the molding surface 2d of the mold piece 4 is provided with, for example, unevenness forming characters, numbers, figures, etc. on the tire 10 in order to enhance the design and decoration of the tire 10 and to display information about the tire 10. It has

The mold body 3 is provided with a first vent hole 3c that opens onto the molding surface 2d. The first vent hole 3c extends linearly from the inner surface portion 3a of the mold body 3 to the outer surface portion 3d. Thereby, the first vent hole 3c communicates the inside and the outside of the side mold 2a. Then, the gas inside the side mold 2a is sucked to the outside through the first vent hole 3c by a suction device (not shown) such as a vacuum pump. The number of first vent holes 3c is not particularly limited.

Further, the mold piece 4 is provided with a second vent hole 4a that opens in the molding surface 2d. The second vent hole 4a extends linearly from the inner surface portion 4b of the mold piece 4 to the outer surface portion 4c. The mold main body 3 includes a through-hole portion 3e that is opened in the outer surface portion 3d and penetrates to the hole portion 3b, and a communicating portion 3f that communicates the second vent hole 4a and the through-hole portion 3e. Thereby, the second vent hole 4a, the communicating portion 3f, and the through-hole portion 3e cooperate to communicate the inside and the outside of the side mold 2a.

Then, the gas inside the side mold 2a is sucked to the outside through the second vent hole 4a, the communicating portion 3f, and the through-hole portion 3e by, for example, an air suction device. Therefore, it is possible to prevent gas from accumulating around the molding surface 2 d of the mold piece 4 , thereby preventing the occurrence of rubber defects in the portion of the tire 10 molded by the mold piece 4 . The number of second vent holes 4a is not particularly limited.

Further, the through-hole portion 3e is formed linearly. Then, when the mold piece 4 is removed from the mold main body 3, a bar-shaped tool X1 is inserted into the through-hole portion 3e, and the outer surface portion 4c of the mold piece 4 is struck by the tool X1. At this time, since the second vent hole 4a is arranged apart from the through-hole portion 3e, it is possible to prevent the second vent hole 4a from being struck by the tool X1. Accordingly, deformation of the second vent hole 4a can be suppressed.

Moreover, the communicating portion 3 f is provided in the mold body 3 . As a result, when the mold piece 4 is driven out from the hole 3b of the mold body 3 by the tool X1, the communication part 3f can be prevented from being struck by the tool X1. Therefore, since deformation of the communication portion 3f can be suppressed, a gas flow path can be reliably formed by the second vent hole 4a, the communication portion 3f, and the through-hole portion 3e.

Although the configuration of the communicating portion 3f is not particularly limited, in the present embodiment, the communicating portion 3f is formed in a groove shape on the bottom surface of the hole portion 3b. As a result, when the mold piece 4 is attached to the mold body 3 , the outer surface portion 4 c of the mold piece 4 is in contact with the bottom surface of the hole 3 b of the mold body 3 .

Therefore, when attaching the mold piece 4 to the mold body 3 , positioning of the mold piece 4 with respect to the mold body 3 is facilitated. Moreover, when the mold piece 4 is attached to the mold body 3 , the mold piece 4 can be stabilized with respect to the mold body 3 . In addition, in FIG. 5, the tool X1 is not shown in cross section.

Moreover, the side mold 2 a has a fixing mechanism 5 for fixing the mold piece 4 to the mold body 3 . Although the configuration of the fixing mechanism 5 is not particularly limited, in the present embodiment, the fixing mechanism 5 includes an elongated male threaded body 5a connected to the mold piece 4 and a female threaded body screwed into the male threaded body 5a. 5b. 4 and 5 (similar to FIG. 7), the male threaded body 5a and the female threaded body 5b are not shown in cross section.

The mold body 3 has an insertion opening portion 3g that communicates with the hole portion 3b and is inserted into the male threaded body 5a, and an engaging opening portion 3h that is opened in the outer surface portion 3d and is locked to the female threaded body 5b. It has Thereby, the mold piece 4 is fixed to the mold main body 3 by screwing the female threaded body 5b into the male threaded body 5a and locking the locking opening 3h.

By the way, if rubber has entered the inside of the vent holes 3c, 4a, it is necessary to clean the inside of the vent holes 3c, 4a using a tool such as a drill after the tire 10 is manufactured. For example, by inserting a drill bit into the vent holes 3c and 4a, the rubber clogging the inside of the vent holes 3c and 4a is removed.

On the other hand, in the side mold 2a according to the present embodiment, the second vent hole 4a is separated from the through hole 3e, and the second vent hole 4a and the through hole 3e are not connected linearly. As a result, for example, when the inside of the vent hole 4a is cleaned with a drill, the tip of the drill blade hits the mold body 3, so that the mold piece 4 attached to the mold body 3 can be removed from the second vent hole 4a. The operation of cleaning the interior is difficult (ie the mold piece 4 has to be removed from the mold body 3).

Therefore, the mold piece 4 is provided with on-off valves 6 for opening and closing the second vent holes 4a for all the second vent holes 4a. As a result, the on-off valve 6 closes the second vent hole 4a, thereby suppressing rubber from entering the inside of the second vent hole 4a. Therefore, the need for cleaning the inside of the second vent hole 4a can be reduced.

In this embodiment, the mold body 3 also has an on-off valve 6 for opening and closing the first vent hole 3c. The mold body 3 may be provided with an on-off valve 6 for opening and closing the first vent holes 3c for all or some of the first vent holes 3c. Therefore, the on-off valve 6 for opening and closing the first vent hole 3c may not be provided.

As shown in FIG. 6, the on-off valve 6 includes a valve seat 7 having a hole 7a through which gas can pass, and a valve body 8 movable between a closed position for closing the hole 7a and an open position for opening the hole 7a. It has The on-off valve 6 also includes a force applying portion 6a that applies a force to the valve body 8 so that the valve body 8 moves from the closed position to the open position. The on-off valve 6 is arranged at the inner end of the vent hole 4a (3c).

The valve seat 7 is fixed inside the vent hole 4a (3c). Specifically, the valve seat 7 is fitted in the vent hole 4a (3c). The valve seat 7 is not limited to being separate from the mold piece 4 (or the mold main body 3), and may be integrated with the mold piece 4 (or the mold main body 3).

The valve seat 7 is cylindrical, and the valve body 8 is arranged inside the valve seat 7 . Specifically, the valve body 8 is inserted into the hole 7a of the valve seat 7 so as to be movable with respect to the valve seat 7 . The valve seat 7 and the valve body 8 are provided with seat surfaces 7b and 8a in contact with each other. The configuration of the force applying portion 6a is not particularly limited, but in the present embodiment, the force applying portion 6a is an elastic body (for example, a coil spring) that applies force to the valve body 8 by elastic force.

In the on-off valve 6 shown in FIG. 6 , the valve body 8 is positioned at the open position where the hole 7 a of the valve seat 7 is opened by the force applying portion 6 a applying force to the valve body 8 . At this time, the seat surface 8 a of the valve body 8 is separated from the seat surface 7 b of the valve seat 7 . As a result, the inside of the tire mold 2 and the vent hole 4a (3c) communicate with each other, so the vent hole 4a (3c) is in an open state.

On the other hand, as the vulcanization of the tire 10 progresses, the pressure inside the tire mold 2 decreases and the rubber comes into contact with the valve body 8 as the rubber approaches the vent hole 4a (3c). Accordingly, the valve body 8 moves against the force from the force applying portion 6a and is positioned at the closed position where the hole 7a of the valve seat 7 is closed. At this time, the seat surface 8 a of the valve body 8 is in contact with the seat surface 7 b of the valve seat 7 . As a result, the inside of the tire mold 2 and the vent hole 4a (3c) are not communicated with each other, so the vent hole 4a (3c) is closed.

As the valve body 8 moves with respect to the valve seat 7 in this manner, the on-off valve 6 opens and closes the vent hole 4a (3c). Although the materials of the valve seat 7 and the valve body 8 are not particularly limited, for example, the valve seat 7 and the valve body 8 may be formed of a metal such as stainless steel or steel. The on-off valve 6 of the first vent hole 3c also has the same configuration as the on-off valve 6 of the second vent hole 4a (but has a different size).

The materials of the mold body 3 and the mold pieces 4 are not particularly limited. It is a configuration that For example, the mold body 3 and the mold pieces 4 may be made of metal such as stainless steel, steel, or aluminum.

Therefore, as the vulcanization of the tire 10 progresses, the mold body 3 and the mold pieces 4 are heated and thermally expanded. Since the mold piece 4 is fitted in the hole 3 b of the mold body 3 , the mold piece 4 receives stress from the mold body 3 . At this time, the stress acts on the weak portion of the mold piece 4, that is, the second vent hole 4a.

Therefore, the average size of the opening area of the second vent holes 4 a in the mold piece 4 is smaller than the average size of the opening area of the first vent holes 3 c in the mold body 3 . As a result, the strength of the second vent hole 4a is prevented from becoming too low, and thus deformation of the second vent hole 4a can be prevented.

In addition, for example, the size of the opening area of all the second vent holes 4a may be smaller than the average size of the opening area of the first vent holes 3c. Further, for example, the size of the opening area of the second vent hole 4a may be smaller than the size of the opening area of all the first vent holes 3c. This can further prevent the strength of the second vent hole 4a from being lowered.

Here, "the average size of the opening area of the first vent holes 3c" means the average size of the opening areas of all the first vent holes 3c provided in the mold body 3. As shown in FIG. Similarly, the “average size of the opening areas of the second vent holes 4 a ” is the average size of the opening areas of all the second vent holes 4 a provided in the mold piece 4 .

Further, "the size of the opening area of each vent hole 3c, 4a" is the average size of the opening area of the vent holes 3c, 4a. That is, the size of the opening area of each vent hole 3c, 4a is a value obtained by dividing the empty volume V1 of each vent hole 3c, 4a by the length L1 of each vent hole 3c, 4a.

As described above, the tire mold 2 according to the present embodiment is the tire mold 2 having the molding surface 2d for molding the tire 10, and the mold body 3 having the hole portion 3b in the inner surface portion 3a constituting the molding surface 2d. and a mold piece 4 which is detachable from the mold main body 3 and fitted into the hole 3b, and the mold piece 4 has a vent hole 4a opened to the molding surface 2d.

According to such a configuration, since the mold piece 4 is provided with the vent hole 4a that opens to the molding surface 2d, it is possible to suppress accumulation of gas around the molding surface 2d of the mold piece 4. FIG. As a result, it is possible to suppress the occurrence of rubber defects in the portion of the tire 10 molded by the mold piece 4 . The tire 10 manufactured by the tire mold 2 according to the present embodiment is a tire 10 in which the occurrence of rubber defects in the portion of the tire 10 molded by the mold pieces 4 is suppressed.

Further, in the tire mold 2 according to the present embodiment, the mold body 3 is opened in the outer surface portion 3d and penetrates to the hole portion 3b because the mold piece 4 is driven out from the hole portion 3b by the tool X1. The vent hole 4a is arranged apart from the through-hole 3e, and the tire mold 2 is provided with a communicating portion 3f that communicates the vent-hole 4a and the through-hole 3e. , is the configuration.

According to such a configuration, the vent hole 4a is arranged away from the through-hole portion 3e, so that when the mold piece 4 is driven out from the hole portion 3b by the tool X1, the vent hole 4a is hit by the tool X1. can be prevented. Thereby, it is possible to suppress deformation of the vent hole 4a. Since the communicating portion 3f communicates the vent hole 4a and the through-hole portion 3e, the gas inside the tire mold 2 can be sucked to the outside.

Further, in the tire mold 2 according to the present embodiment, the mold piece 4 is provided with an on-off valve 6 for opening and closing the vent hole 4a, and the on-off valve 6 is a cylindrical valve fixed inside the vent hole 4a. and a valve element 8 movable between a closed position for closing the vent hole 4a and an open position for opening the vent hole 4a.

According to such a configuration, since the vent hole 4a is arranged away from the through-hole 3e, it is difficult to clean the inside of the vent hole 4a with the mold piece 4 attached to the mold body 3. For some reason, the on-off valve 6 opens and closes the vent hole 4a. As a result, rubber can be prevented from entering the inside of the vent hole 4a by positioning the valve body 8 at the closed position.

Further, in the tire mold 2 according to the present embodiment, the mold body 3 and the mold pieces 4 have thermal expansibility, and the mold body 3 is provided with vent holes 3c that open to the molding surface 2d. , the average size of the opening areas of the vent holes 4 a of the mold piece 4 is smaller than the average size of the opening areas of the vent holes 3 c of the mold body 3 .

According to such a configuration, the opening area of the vent hole 4a of the mold piece 4 is large against the stress acting on the vent hole 4a of the mold piece 4 due to the thermal expansion of the mold body 3 and the mold piece 4. height is getting smaller. This prevents the strength of the vent hole 4a of the mold piece 4 from becoming too low.

In addition, the tire mold 2 and the tire 10 are not limited to the configurations of the above-described embodiments, and are not limited to the above-described effects. Moreover, the tire mold 2 and the tire 10 can of course be modified in various ways without departing from the gist of the present invention. For example, it is of course possible to arbitrarily select one or a plurality of configurations, methods, etc., according to various modified examples described below and employ them in the configurations, methods, etc., according to the above-described embodiment.

(1) In the tire mold 2 according to the above embodiment, the tire mold 2 including the mold piece 4 having the vent hole 4a and the mold body 3 is the side mold 2a. However, the tire mold 2 is not limited to such a configuration. Specifically, the tire mold 2 including the mold piece 4 having the vent hole 4a and the mold body 3 may be at least one of the side mold 2a, the tread mold 2b, and the bead mold 2c. .

(2) In addition, in the tire mold 2 according to the above-described embodiment, the vent hole 4a and the through-hole portion 3e are in communication with each other via the communication portion 3f. However, the tire mold 2 is not limited to such a configuration. For example, as shown in FIG. 7, the vent hole 4a may be in direct communication with the through-hole 3e.

(3) Further, in the tire mold 2 according to the above-described embodiment, the mold pieces 4 are configured to have the on-off valves 6 in all of the second vent holes 4a. However, the tire mold 2 is not limited to such a configuration. For example, the mold piece 4 may be configured such that a part of the second vent holes 4a is provided with the on-off valve 6. As shown in FIG.

Further, for example, as shown in FIG. 7, the mold piece 4 may have a configuration in which none of the second vent holes 4a are provided with the on-off valves 6 . In a configuration in which the opening/closing valve 6 is not provided in the second vent hole 4a, the inside of the second vent hole 4a can be cleaned with the mold piece 4 attached to the mold body 3, as shown in FIG. In addition, the vent hole 4a and the through hole 3e may directly communicate with each other so as to form a straight line.

(4) Further, in the tire mold 2 according to the above-described embodiment, the communicating portion 3f is provided in the mold body 3. As shown in FIG. However, the tire mold 2 is not limited to such a configuration. For example, the communication portion may be provided in the mold piece 4 , and as an example, the communication portion may be formed in a groove shape on the outer surface portion 4 c of the mold piece 4 . Alternatively, the communicating portion may be formed in a gap between the bottom portion of the hole portion 3b of the mold body 3 and the outer surface portion 4c of the mold piece 4. FIG.

(5) In the tire mold 2 according to the above embodiment, the average size of the opening area of the second vent holes 4a of the mold piece 4 is the size of the opening area of the first vent holes 3c of the mold body 3. is smaller than the average of However, the tire mold 2 is not limited to such a configuration. For example, the average size of the opening areas of the second vent holes 4a may be greater than or equal to the average size of the opening areas of the first vent holes 3c.

REFERENCE SIGNS LIST 1 tire vulcanizer 1a molding chamber 1b side base 1c tread base 1d first moving mechanism 2 tire mold 2a side mold 2b tread mold 2c bead mold 2d Molding surface 3 Mold body 3a Inner surface 3b Hole 3c First vent hole 3d Outer surface 3e Through opening 3f Communicating portion 3g Insertion opening 3h Locking opening 4 Molded piece 4a Second vent hole 4b Inner surface 4c Outer surface 5 Fixing mechanism 5a Male threaded body 5b Female threaded body 6 On-off valve 6a ... Loading portion 7 ... Valve seat 7a ... Hole 7b ... Seat surface 8 ... Valve body 8a ... Seat surface 10 ... Tire 11 ... Bead portion 12 ... Sidewall portion 13 ... Tread portion D1 ... tire width direction, D2 ... tire radial direction, D3 ... tire circumferential direction, X1 ... tool

Claims (4)

In a tire mold having a molding surface for molding a tire,
a mold body having a hole in the inner surface constituting the molding surface;
a mold piece that is detachable from the mold body and is fitted into the hole,
The mold piece has a vent hole opened in the molding surface ,
The mold body has a through-hole that is open to the outer surface and penetrates to the hole for the mold piece to be driven out from the hole by a tool,
The vent hole is arranged away from the through-hole,
The tire mold is provided with a communicating portion that communicates the vent hole and the through-hole portion . The mold piece includes an on-off valve that opens and closes the vent hole,
The on-off valve includes a cylindrical valve seat fixed inside the vent hole, and a valve element movable between a closed position for closing the vent hole and an open position for opening the vent hole. The tire mold of Claim 1 . The mold body and the mold pieces have thermal expansibility,
The mold body has a vent hole opened in the molding surface,
3. The tire mold according to claim 1 , wherein the average size of the opening area of the vent holes in the mold piece is smaller than the average size of the opening area of the vent holes in the mold body. A tire manufacturing method comprising a step of vulcanizing an unvulcanized tire with the tire mold according to any one of claims 1 to 3 .

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