HEATING PRESS AND METHOD FOR VULCANIZING A VEHICLE TIRE IN SAID HEATING PRESS UNDER VACUUM

Abstract

A heating press (1) for vulcanizing a vehicle tire under a vacuum, having a heating press upper part (3) and a heating press lower part (6), wherein the heating press upper part (3) has a hood upper part (4) mounted thereon and a container (2), which contains mold parts (16, 18, 21) of a segmented vulcanizing mold, in this hood upper part (4), wherein the hood upper part (4) has a first circular ring (23), which is arranged fixedly on the heating press upper part (3), and a second circular ring (24), which adjoins this first circular ring coaxially in an axial direction and can be telescopically retracted and extended out over the first circular ring (23) in an axial direction P1, wherein vacuum-tight seals (5, 9) are arranged between the two circular rings (23, 24) and between the second circular ring (24) and the heating press lower part (6), wherein, after a first partial stroke (TH.sub.1), the hood upper part (3) can be moved in such a way that it rests on the heating press lower part (6) by way of the extended second circular ring (24), and the interior space of the hood (12) can be closed in a vacuum-tight manner by the seals (5, 9) although the vulcanizing mold is still open in an air-permeable manner and wherein a pump (10) and a vacuum tank (11), by means of which a vacuum can be generated in the interior space of the hood (12) after the first partial stroke (TH.sub.1), are provided, wherein, after a second partial stroke (TH.sub.2), the hood upper part (3) can be moved in such a way that the second circular ring (24) can be retracted out further over the first circular ring (23) and the vulcanizing mold can be completely closed under vacuum conditions in the interior space of the hood (12).

Claims

1-12. (canceled)

13. A heating press for vulcanizing a vehicle tire, the press comprising: a heating press upper part; a heating press lower part; the heating press upper part having a hood upper part mounted thereon and a container, the hood upper part has a first circular ring arranged on the heating press upper part and a second circular ring that adjoins the first circular ring coaxially in an axial direction, the second circular ring configured to be telescopically retracted and extended out over the first circular ring in an axial direction P1; the heating press upper part and the heating press lower part are connected to the container so when the heating press upper part is lowered through a total stroke (GH) that takes place in the axial direction (P1), during which an open end of the hood upper part moves onto the heating press lower part, mold parts of a vulcanizing mold are closed in a radial direction (P2); vacuum-tight seals are arranged between the first and second circular rings, the second circular ring, and the heating press lower part; the total stroke (GH) can be travelled in a first partial stroke (TH1) and a second partial stroke (TH2); after the first partial stroke (TH1), the hood upper part is moved to rest on the heating press lower part by the second circular ring as extended and an interior space of the hood is closed in a vacuum-tight manner by seals although the vulcanizing mold is still open in an air-permeable manner; a pump and a vacuum tank to generate a vacuum in the interior space of the hood after the first partial stroke (TH1); the hood upper part is moved to permit the second circular ring to be retracted out further over the first circular ring and the vulcanizing mold can be completely closed under vacuum conditions of the interior space of the hood.

14. The heating press of claim 13, further comprising a hydraulic, pneumatic or electric actuator (26), which can move the second circular ring (24) of the hood upper part (3) in an axial direction (P1).

15. The heating press of claim 13, wherein a hood lower part (7) in the form of a third circular ring is arranged on the heating press lower part (6), wherein the first circular ring (23) of the hood upper part (3) and the third circular ring of the hood lower part (7) have the same inside diameter and the same outside diameter and are arranged in line with one another in the heating press (1).

16. The heating press of claim 13, wherein the seals are ring seals (5, 9), and at least one ring seal (9) is arranged in the lower region of the hood upper part (4) and at least one further ring seal (9) is arranged in the upper region of the hood lower part (7).

17. The heating press of claim 16, wherein the ring seals (5, 9) are arranged in circular-ring-shaped grooves (25), wherein the diameter of the ring seals (5, 9) is slightly greater than the depth of the grooves (25).

18. The heating press of claim 16, wherein the ring seals (5, 9) consist of solid material.

19. The heating press of claim 16, wherein the ring seals (5, 9) are hoses of variable diameter.

20. The heating press of claim 16, wherein the ring seals (5, 9) are differentially inflated double ring seals.

21. The heating press of claim 13, wherein sliding bands composed of wear-resistant high-temperature polymer, for example of PEEK, are arranged in the hood parts (4, 7) in the region above and/or below the ring seals (9).

22. The heating press of claim 13, wherein the vacuum tank (11) has a volume that is approximately 5 to 10 times greater than the volume of the closed hoods (4, 7).

23. A method for vulcanizing a pneumatic vehicle tire under a vacuum, the method comprising: a) loading the open heating press (1) by inserting the green tire for vulcanization into the container (2), wherein the second circular ring (24) of the hood upper part (4) is retracted out over the first circular ring (23), b) moving the heating press upper part (3) through the first partial stroke (TH1), extending the second circular ring (24) toward the heating press lower part (6) until it rests on the heating press lower part (6), in order to obtain a closed hood interior space (12), while the vulcanizing mold is only closed to some extent, c) only if the ring seals (5, 9) are a hose of variable diameter: inflating the circular-ring-shaped hose seal in order to seal off the hood interior space (12) in a vacuum-tight manner, d) opening the connection between the vacuum tank (11) and the hood interior space (12) in order to generate a partial vacuum, by way of pressure equalization between the vacuum tank (11) and the hood interior space (12), in the hood interior space (12) that has been closed in a vacuum-tight manner, e) when the partial vacuum is obtained in the hood interior space (12): closing the connection between the vacuum tank (11) and the hood interior space (12), opening the connection between the hood interior space (12) and the pump (10), and pumping the remaining air out of the hood interior space (12) in order to generate the vacuum, f) moving the heating press upper part (3) through the second partial stroke (TH2), during which the second circular ring (24) is retracted out over the first circular ring (23), with the result that the vulcanizing mold is completely closed, and subsequently closing the connection between the hood interior space (12) and the pump (10), g) vulcanizing the green tire and opening the connection between the pump (10) and the vacuum tank (11) and generating a vacuum in the vacuum tank (11), wherein the connection of the pump (10) to the hood interior space (12) and the connection of the vacuum tank (11) to the hood interior space (12) are each closed, h) opening the heating press (1) and unloading the fully vulcanized tire, and repeating the steps a)-h) in order to vulcanize each further tire.

24. The method of claim 23, wherein to facilitate step h), this is preceded by opening a further valve arranged in the hoods (4, 7) in order to deplete the vacuum and subsequently closing it again.

Description

[0046] An exemplary embodiment of a heating press and the method for vacuum vulcanization of a pneumatic vehicle tire, together with further advantages, will be described on the basis of the following schematic FIGS. 1 to 4. In the figures:

[0047] FIG. 1 shows a first embodiment of a heating press according to the invention with a container in the open state;

[0048] FIG. 2 shows the heating press of FIG. 1 in the closing phase after a first partial stroke;

[0049] FIG. 3 shows the heating press of FIG. 1 and of FIG. 2 in the closed state after a second partial stroke;

[0050] FIG. 4 shows a second embodiment of a heating press according to the invention with a container in the open state;

[0051] FIG. 5 shows the heating press of FIG. 4 in the closing phase after a first partial stroke;

[0052] FIG. 6 shows the heating press of FIG. 4 and of FIG. 5 in the closed state after a second partial stroke;

[0053] FIG. 7 shows a third embodiment of a heating press according to the invention with a container in the open state;

[0054] FIG. 8 shows the heating press of FIG. 7 in the closing phase after a first partial stroke;

[0055] FIG. 9 shows the heating press of FIG. 7 and of FIG. 8 in the closed state after a second partial stroke;

[0056] FIG. 10 shows a fourth embodiment of a heating press according to the invention with a container in the open state;

[0057] FIG. 11 shows the heating press of FIG. 10 in the closing phase after a first partial stroke.

[0058] FIG. 1 shows a first embodiment of a heating press 1 according to the invention with a container 2 in the open state. The green tire can be placed into the heating press 1.

[0059] The heating press 1 comprises a heating press upper part 3, which is connected to the hood upper part 4, and a heating press lower part 6, which is connected to the hood lower part 7 and has the corresponding mechanisms for positioning the tire for vulcanization, for actuating the constituent parts of the vulcanizing mold, for introducing the heating media, and for removing the fully vulcanized tire. During the vulcanization operation, the container 2 is enclosed by the two-part hood 4, 7. The hood upper part 4 has a first and a second circular ring 23, 24, wherein the second circular ring 24 is provided with a greater diameter than the first circular ring 23. The second circular ring 24 can be telescopically retracted and extended on the first circular ring 23 in an axial direction P1 by means of an actuator 26. The hood lower part 7 has a third circular ring. The third circular ring 7 and the first circular ring 23 of the hood upper part 3 have the same inside diameter and the same outside diameter and are arranged with their end faces in line in the heating press 1. The diameter of the second circular ring 24 of the hood upper part 4 is slightly greater than the diameter of the third circular ring 7 of the hood lower part.

[0060] A “central mechanism” 8 is provided. This is likewise charged with seals—to the extent necessary—in order to establish vacuum-tightness between the central mechanism and the heating press upper and lower parts. A heating bellows (not illustrated) that can be placed into the green tire (not illustrated) is fastened to the central mechanism 8. Furthermore, nozzles (not illustrated) are arranged on the central mechanism 8, through which nozzles a heating medium can be introduced into the heating bellows (not illustrated).

[0061] The hood upper part 4 and the hood lower part 7 are airtight, or vacuum-tight, and in the closed state form a vacuum-tight hood interior space 12. To that end, ring seals 5, 9 are provided. A ring seal 9 is arranged between the first and the second circular ring 23, 24 in a groove 25, which is arranged in the first circular ring 23 and faces the second circular ring 24, for an airtight hood upper part 3. Similarly, a ring seal 9 is arranged around the periphery in a groove 25, corresponding to that in the first circular ring 23, in the third circular ring 7 on its outer side. A further horizontal ring seal 5 is arranged in line with the second circular ring 24 in a groove 25 which is open toward the heating press upper part 3. Therefore, the closed hood is airtight at the joints between the hood upper part 3 and the hood lower part 7, and between the first and the second circular ring 23, 24. The ring seal 5, 9 is a hose of variable diameter. The diameter of the ring seal 5, 9 is slightly greater than the depth 27 of the groove 25.

[0062] A vacuum can be generated in the hood interior space (=interior space of the hood) 12 by means of a pump 10 and a vacuum tank 11, wherein the vacuum tank 11 and the pump 10 are connected to the interior space 12 of the hood, and wherein the vacuum tank 11 and the pump 10 are connected to one another. By virtue of a vacuum being provided in the hood interior space 12, in particular during the molding and the vulcanization of the tire, conventional ventilation valves arranged in the mold face of the vulcanizing mold are omitted entirely.

[0063] The container 2 is a conventional container 2 that is already known in the prior art.

[0064] The container 2 contains the segmented vulcanizing mold with a lower heating plate 13, a lower sidewall shell 14, an upper heating plate 15, an upper sidewall shell 16, a lower bead ring 17 and an upper bead ring 18. Those constituent parts of the vulcanizing mold that are moved in a vertical (=axial) direction (arrow P1) for the purposes of opening and closing include the segment ring 19, composed of seven to nine segment shoes 20, and the profile/mold segments 21 fastened thereto and also the upper sidewall shell 16 with the upper bead ring 18. The segment shoes 20 are moved apart radially, in the direction of the arrow P2, to close and open the vulcanization mold. On the upper heating plate 15, there is arranged a closing ring 22 which has a beveled inner surface which interacts with beveled outer surfaces of the segment shoes 20 of the segment ring 19 such that, during the closing of the vulcanizing mold, the segment shoes 20 are moved together in a radial direction to form the closed segment ring 19. In the lower heating plate 13, the upper heating plate 15 and in the closing ring 22, there are incorporated heating chambers into which at least one heating medium, in particular saturated steam (water vapor), is introduced for the vulcanization of the tire. In this way, the green tire (not illustrated) is heated from the outside via the segment shoes 20, the sidewall shells 14, 16 and the bead rings 17, 18, such that this heating is commonly referred to as external heating.

[0065] A conventional heating bellows (not illustrated) is provided in a known manner and is filled with at least one pressurized heating medium in order to center the green tire in the mold from the inside, wherein the heating bellows is brought into a toroidal shape conforming to a tire. Since the green tire is heated by means of the heating bellows from the inside, this type of heating is referred to as internal heating.

[0066] In FIG. 1, the heating press 1 is open, with the second circular ring 24 of the hood upper part 3 having been telescopically retracted over the first circular ring 23. The green tire can be placed into the container 2.

[0067] FIG. 2 illustrates the heating press 1 of FIG. 1 in the closing phase after a first partial stroke TH.sub.1.

[0068] The heating press upper part 3 is moved through the first partial stroke TH.sub.1 and the second circular ring 24 is extended toward the heating press lower part 7, with the result that it rests on the heating press lower part 7 in the region of the horizontal ring seal 5 and overlaps the third circular ring 7 in the region of the ring seal 9. The ring seal 9 seals off the small intermediate space between the second circular ring 24 of the hood upper part 4 and the third circular ring 7 of the hood lower part when the second circular ring 24 rests on the hood lower part. A closed, vacuum-tight hood interior space 12 is obtained, while the vulcanization mold is closed only to some extent. If the ring seals 5, 9 are a hose of variable diameter, they are inflated in order to seal off the hood 4, 7 in a vacuum-tight manner. The connection between the vacuum tank 11 and the hood interior space 12 is opened in order to generate a partial vacuum, by way of pressure equalization between the vacuum tank 11 and the hood interior space 12, in the hood interior space 12 that has been closed in a vacuum-tight manner. When the partial vacuum has been generated in the hood interior space 12, the connection between the vacuum tank 11 and the hood 4, 7 is closed, the connection between the hood interior space 12 and the pump 10 is opened and the remaining air is pumped out of the hood interior space 12 to generate the vacuum.

[0069] FIG. 3 shows the heating press of FIG. 1 and of FIG. 2 in the closed state after a second partial stroke TH.sub.2. After a vacuum has been generated in the interior space 12 of the closed hood 4, 7 of FIG. 2, the performance of a second partial stroke TH.sub.2, during which the second circular ring 24 is retracted out over the first circular ring 23, then causes the vulcanizing mold, which has been evacuated of air, to be completely closed and the connection between the vacuum tank 11 and the hood 4, 7 to be closed.

[0070] Then, the connection between the hood interior space 12 and the pump 10 is closed. The green tire is vulcanized.

[0071] The sum of the first partial stroke TH1 and the second partial stroke TH.sub.2 yields the total stroke GH. The tire is vulcanized. In the case of a passenger motor vehicle tire, the vulcanization thereof takes approximately 15 minutes. During this time, the connection between pump 10 and vacuum tank 11 is opened in order to generate a vacuum in the vacuum tank 11, wherein the connection of the pump 10 to the hood 4, 7 and the connection of the vacuum tank 11 to the hood 4, 7 are each closed. After the vulcanization of the tire is complete, the volume of the hood interior space 12 is aerated via a valve (not illustrated), and the heating press 1 is opened in order to unload the fully vulcanized tire from the container 2 having the vulcanizing mold. To that end, the hood upper part 4 is first of all advanced, the second circular ring 24 is retracted out over the first circular ring 23, and the profile segments 21 are moved outward in a radial direction P2 at the same time. The tire is released.

[0072] In the following further embodiments of a heating press 1 according to the invention that are shown in FIGS. 4 to 11, almost all the elements and functions have the same configuration as in the first embodiment. Differences exist only in terms of the relative size of the diameter of the second circular ring 24 of the hood upper part 4 to the diameter of the third circular ring 7 of the hood lower part. Therefore, merely a different arrangement of the sealing ring 9 between the second circular ring 24 of the hood upper part 4 and the third circular ring 7 of the hood lower part will be discussed.

[0073] Therefore, merely the first circular ring 23 and the second circular ring 24 of the hood upper part and the third circular ring 7 of the hood lower part, and the vacuum-tight seals between the two circular rings 23, 24 of the hood upper part and between the second circular ring 24 of the hood upper part and the third circular ring of the hood lower part, are provided with reference signs.

[0074] All other elements of the heating press are not explicitly provided with reference signs and the means, connected to the heating press, for generating a vacuum in the interior space of the hood of the heating press, such as the pump 10, the vacuum tank 11 and associated lines and valves, are not shown in FIGS. 4 to 11 for the sake of simplicity, even though they are present in the heating presses shown in the same way as in FIGS. 1 to 3. The elements of the heating press that are not provided with reference signs and the means, which are not shown, for generating a vacuum in the interior space of the hood of the heating press have already been described in connection with the first embodiment, as have their function and the overall mode of operation of a heating press according to the invention.

[0075] FIG. 4 shows a second embodiment of a heating press according to the invention with a container 2 in the open state. The hood upper part has a first and a second circular ring 23, 24, wherein the second circular ring 24 is provided with a greater diameter than the first circular ring 23. The second circular ring 24 can be telescopically retracted and extended on the first circular ring 23 in an axial direction P1 by means of an actuator 26. The hood lower part 7 has a third circular ring. The diameter of the second circular ring 24 of the hood upper part is exactly the same size as the diameter of the third circular ring 7 of the hood lower part.

[0076] The hood upper part 4 and the hood lower part 7 are airtight, or vacuum-tight, and in the closed state form a vacuum-tight hood interior space 12. To that end, ring seals 9 are provided. A ring seal 9 is arranged between the first and the second circular ring 23, 24 in a groove 25, which is arranged in the first circular ring 23 and faces the second circular ring 24, for an airtight hood upper part 4. Similarly, the third circular ring 23 has a vacuum-tight ring seal 9 around the periphery at its upper end. Therefore, the closed hood is airtight at the joints between the hood upper part 4 and the hood lower part 7, and between the first and the second circular ring 23, 24. The ring seal 9 is a hose of variable diameter. The diameter of the ring seal 9 is slightly greater than the depth 27 of the groove 25 in which it is arranged.

[0077] FIG. 5 illustrates the heating press 1 of FIG. 4 in the closing phase after a first partial stroke TH.sub.1.

[0078] The heating press upper part 3 is moved through the first partial stroke TH.sub.1 and the second circular ring 24 is extended toward the heating press lower part 7, with the result that it rests on the third circular ring 7 of the heating press lower part 7. The ring seal 9 at the upper end of the third circular ring 7 then provides sealing between the second circular ring 24 of the hood upper part 4 and the third circular ring 7 of the hood lower part when the second circular ring 24 rests on the hood lower part. A closed, vacuum-tight hood interior space 12 is obtained, while the vulcanization mold is closed only to some extent. If the ring seals 9 are a hose of variable diameter, they are inflated in order to seal off the hood 4, 7 in a vacuum-tight manner.

[0079] FIG. 6 shows the heating press of FIG. 4 and of FIG. 5 in the closed state after a second partial stroke TH.sub.2. After a vacuum has been generated in the interior space 12 of the closed hood 4, 7 of FIG. 5, the performance of a second partial stroke TH.sub.2, during which the second circular ring 24 is retracted out over the first circular ring 23, then causes the vulcanizing mold, which has been evacuated of air, to be completely closed.

[0080] FIG. 7 shows a third embodiment of a heating press according to the invention with a container 2 in the open state. The hood upper part 4 has a first and a second circular ring 23, 24, wherein the second circular ring 24 is provided with a greater diameter than the first circular ring 23. The second circular ring 24 can be telescopically retracted and extended on the first circular ring 23 in an axial direction P1 by means of an actuator 26. The hood lower part 7 has a third circular ring. The diameter of the second circular ring 24 of the hood upper part is slightly less than the diameter of the third circular ring 7 of the hood lower part.

[0081] The hood upper part 4 and the hood lower part 7 are airtight, or vacuum-tight, and in the closed state form a vacuum-tight hood interior space 12. To that end, ring seals 9 are provided. A ring seal 9 is arranged between the first and the second circular ring 23, 24 in a groove 25, which is arranged in the first circular ring 23 and faces the second circular ring 24, for an airtight hood upper part 4. Similarly, the third circular ring 23 has a vacuum-tight ring seal 9 around the periphery on its inner side. Therefore, the closed hood is airtight at the joints between the hood upper part 4 and the hood lower part 7, and between the first and the second circular ring 23, 24. The ring seal 9 is a hose of variable diameter. The diameter of the ring seal 9 is slightly greater than the depth 27 of the groove 25 in which it is arranged.

[0082] FIG. 8 illustrates the heating press 1 of FIG. 7 in the closing phase after a first partial stroke TH.sub.1.

[0083] The heating press upper part 3 is moved through the first partial stroke TH.sub.1 and the second circular ring 24 is extended toward the heating press lower part 7, with the result that it rests on the heating press lower part 7. The ring seal 9 on the inner side of the third circular ring 7 then seals off the small intermediate space between the second circular ring 24 of the hood upper part 4 and the third circular ring 7 of the hood lower part when the second circular ring 24 rests on the hood lower part. A closed, vacuum-tight hood interior space 12 is obtained, while the vulcanization mold is closed only to some extent. If the ring seals 9 are a hose of variable diameter, they are inflated in order to seal off the hood 4, 7 in a vacuum-tight manner.

[0084] FIG. 9 shows the heating press of FIG. 7 and of FIG. 8 in the closed state after a second partial stroke TH.sub.2. After a vacuum has been generated in the interior space 12 of the closed hood 4, 7 of FIG. 8, the performance of a second partial stroke TH.sub.2, during which the second circular ring 24 is retracted out over the first circular ring 23, then causes the vulcanizing mold, which has been evacuated of air, to be completely closed.

[0085] FIG. 10 shows a fourth embodiment of a heating press according to the invention with a container 2 in the open state. The embodiment differs from the previously described third embodiment merely in that an elastically extensible, vacuum-tight rubber sleeve 28 is provided as additional vacuum-tight seal between the first circular ring 23 and the second circular ring 24 of the hood upper part. This is secured in a circular shape on the inside of the lower part of each of the two circular rings 23, 24.

[0086] FIG. 11 illustrates the heating press 1 of FIG. 10 in the closing phase after a first partial stroke TH.sub.1.

[0087] The heating press upper part 3 is moved through the first partial stroke TH.sub.1 and the second circular ring 24 is extended toward the heating press lower part 7, with the result that it rests on the heating press lower part 7. This causes the rubber sleeve 28, which is fastened to both circular rings 23, 24, to extend in the direction of the stroke.

LIST OF REFERENCE SIGNS

Part of the Description

[0088] 1 Heating press [0089] 2 Container [0090] 3 Heating press upper part [0091] 4 Hood upper part [0092] 5 Ring seal [0093] 6 Heating press lower part [0094] 7 Hood lower part=third circular ring [0095] 8 Central mechanism [0096] 9 Ring seal [0097] 10 Pump [0098] 11 Vacuum tank [0099] 12 Interior space of the hood [0100] 13 Lower heating plate [0101] 14 Lower sidewall shell [0102] 15 Upper heating plate [0103] 16 Upper sidewall shell [0104] 17 Lower bead ring [0105] 18 Upper bead ring [0106] 19 Segment ring [0107] 20 Segment shoe [0108] 21 Profile segment/mold segment [0109] 22 Closing ring [0110] 23 First circular ring [0111] 24 Second circular ring [0112] 25 Groove [0113] 26 Actuator [0114] 27 Depth of the groove [0115] 28 Rubber sleeve [0116] TH.sub.1 First partial stroke [0117] TH.sub.2 Second partial stroke [0118] GH Total stroke