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

Description

[0001] The invention relates to a heating press for vulcanizing a vehicle tire, comprising an upper heating press part and a lower heating press part, the upper heating press part having a hood upper part mounted thereon and a container containing a molded part of a vulcanizing mold in this hood upper part, the upper heating press part and the lower heating press part being connected to the container in such a way that when the upper heating press part is moved down over a total stroke in the axial direction, during which the open end of the hood upper part moves onto the lower heating press part, the molded parts of the vulcanizing mold can be closed in the radial direction.

[0002] The invention further relates to a method for vulcanizing a green tire in the aforementioned heating press.

[0003] The heating press described above is a standard heating press for vulcanizing vehicle tires under atmospheric conditions.

[0004] Such a vulcanizing press is known from patent application DE 17 79 130 A1. The upper part of the heating press is a dome consisting of a cylindrical element as the upper hood and an upper press plate. In the press, the interior of the molded parts can be placed under vacuum before they are closed, with the mold then surrounded by a chamber sealed from the surrounding atmosphere.

[0005] The curing press comprises a so-called container, which contains the actual segmented vulcanizing mold with the tire-shaping mold segments, sidewall shells, and bead rings. Heating chambers are also provided for tempering the molded parts. During vulcanization, the container is surrounded by a closed hood, which, in the prior art, primarily serves to insulate the temperature during vulcanization.

[0006] To minimize imperfections on the tire surface, the air between the green tire surface and the mold surface must be removed. For this purpose, it is generally known that 1,000 to 5,000 vent valves must be provided in the mold surfaces of the molded parts. These vent valves discharge the air from the mold cavity radially and axially outward through vent channels. However, the molded parts of a new vulcanizing mold must be equipped with these valves. Furthermore, these valves tend to become dirty due to rubber from the tire being vulcanized penetrating them, so they must be replaced or cleaned at great expense.

[0007] The invention is based on the object of providing a heating press for vulcanizing a vehicle tire under vacuum, with which vehicle tires can be reliably vulcanized without the need for vent valves in the vulcanizing mold. It is also the object of the invention to provide a method for the time-efficient vulcanization of a vehicle tire.

[0008] The task is solved with regard to the heating press by the hood upper part has a first circular ring fixedly arranged on the heating press upper part and a second circular ring axially adjoining this first circular ring and displaceable outwardly in the axial direction P1 over the first circular ring; vacuum-tight seals are arranged between the two circular rings as well as the second circular ring and the heating press lower part; the total stroke (GH) is movable from a first partial stroke (TH 1 ) and a second partial stroke (TH 2 ); after the first partial stroke, the hood upper part is movable in such a way that it rests with the second circular ring on the heating press lower part and the interior of the hood upper part is vacuum-tightly closed by the seals, while the vulcanization mold, however, is still open and permeable to air; and a pump and a vacuum tank are arranged to generate a vacuum in the interior of the hood before the vulcanization mold is completely closed;by means of which a vacuum can be generated in the interior of the hood after the first partial stroke, wherein the vacuum tank and the pump are connected to the interior of the hood and wherein the vacuum tank and the pump are connected to each other and after the second partial stroke the upper part of the hood can be moved in such a way that the second circular ring can be moved further outwards relative to the first circular ring and the vulcanising mould can be closed hermetically under vacuum conditions in the interior of the hood.

[0009] The vacuum that can be achieved after the first partial stroke serves to remove the air from the vulcanizing mold that is not yet completely closed, in particular between the outer surface of the tire and the molding surfaces of the forming parts of the vulcanizing mold, in order to be able to produce the tire to be vulcanized with high quality and without defects after the second partial stroke, by which the vulcanizing mold can be completely closed.

[0010] The term "circular ring" means "cylinder with an approximately circular cross-section".

[0011] Another important feature is that the vulcanizing mold itself does not have any venting devices for venting the mold cavity. Vulcanization under vacuum eliminates the need for the 1,000 to 5,000 venting valves typically found in the vulcanizing mold, which are used in the prior art to radially vent the air from the mold cavity. This eliminates the need to rework the rubber vents on the tire created by the venting devices, and eliminates the need to replace or clean deflated vent valves. This saves time and money. Furthermore, vacuum vulcanization gives the vulcanized tire an external shape that is completely free of defects and thus appears perfect.

[0012] Another essential feature of the invention is that the hood upper part has two circular rings, the first of which is fixedly mounted on the heating press upper part, and the second of which is telescopically movable outside over the first circular ring. This ensures that – when both circular rings of the hood upper part are extended and the hood is lowered onto the heating press lower part – a vacuum-tight interior of the hood around the container is maintained by means of the arranged seals, although the vulcanization mold is not yet completely closed. It is expressly stated that no modifications to the container or the vulcanization mold itself regarding vacuum-sealing measures should be made.

[0013] The term vacuum refers to air pressure in the range from 950 mbar (abs) to 0.1 mbar (abs). The ring seal preferably has a round, square, or flat cross-section.

[0014] It is expedient if a hydraulic, pneumatic or electric actuator is arranged by means of which the second circular ring of the hood upper part can be moved in the axial direction.

[0015] Preferably, a hood lower part in the form of a third circular ring is arranged on the lower part of the heating press. Depending on the ratio of the diameter of the second circular ring of the hood upper part to the diameter of the third circular ring of the hood lower part, there is then a different arrangement of the sealing ring between the second circular ring of the hood upper part and the third circular ring of the hood lower part.

[0016] If the diameter of the second circular ring of the hood upper part is slightly larger than the diameter of the third circular ring of the hood lower part, either the third circular ring has a circumferential vacuum-tight seal on its outer side, or the second circular ring has a circumferential vacuum-tight seal on its inner side. The seal seals the small gap between the second circular ring of the hood upper part and the third circular ring of the hood lower part when the second circular ring is seated on the hood lower part. This is the case when at least the first partial stroke (TH 1 ) of the total stroke (GH) has been traveled by the heating press.

[0017] If the diameter of the second circular ring of the hood's upper section is exactly the same as the diameter of the third circular ring of the hood's lower section, either the third circular ring has a circumferential vacuum-tight seal at its upper end, or the second circular ring has a circumferential vacuum-tight seal at its lower end. The seal then seals when the second circular ring rests on the third circular ring of the hood's lower section. This is the case when at least the first partial stroke (TH 1 ) of the total stroke (GH) has been completed by the heating press.

[0018] If the diameter of the second circular ring of the hood upper part is slightly smaller than the diameter of the third circular ring of the hood lower part, either the third circular ring has a circumferential vacuum-tight seal on its inner side, or the second circular ring has a circumferential vacuum-tight seal on its outer side. The seal seals the small gap between the second circular ring of the hood upper part and the third circular ring of the hood lower part when the second circular ring is seated on the hood lower part. This is the case when at least the first partial stroke (TH 1 ) of the total stroke (GH) has been traversed by the heating press.

[0019] In a specific embodiment of the invention, a hood lower part in the form of a third circular ring is arranged on the heating press lower part, wherein the first circular ring of the hood upper part and the third circular ring of the hood lower part have the same inner diameter and the same outer diameter and are arranged in alignment with one another in the heating press. This ensures a very reliable seal of the hood interior, especially if a sealing ring is arranged on the upper end of the third circular ring or at the lower end of the first circular ring.

[0020] In this embodiment, the third circular ring preferably also has a vacuum-tight seal running around its outer surface, which seals between the second circular ring of the hood upper part and the third circular ring of the hood lower part when the second circular ring rests on the hood lower part. This is the case when at least the first partial stroke (TH 1 ) of the total stroke (GH) has been completed by the heating press.

[0021] It is advantageous if the seals are ring seals, with at least one ring seal located in the lower area of ​​the hood's upper section and at least one further ring seal located in the upper area of ​​the hood's lower section. The vacuum is created by ensuring that the first and second circular rings of the hood's upper section and the third circular ring of the hood's lower section are sealed against each other by at least one ring seal each.

[0022] For reliable sealing performance, it is advisable to arrange the ring seals in annular grooves, with the diameter of the ring seals slightly larger than the depth of the grooves. Slightly larger means that the seal is compressed by a maximum of 40% when installed in the groove and in the sealed state compared to the compression-free geometry of the seal. The precise design of the groove in relation to the seal geometry prevents damage to the seal(s) due to (relative) movement of the two or three circular rings and improves durability.

[0023] In one embodiment of the invention, the ring seal is made of solid material. The solid material can be made of one or more materials known for sealing, such as FKM or FFKM. These seals are cost-effective and easy to handle.

[0024] In another embodiment of the invention, the ring seals are hoses with adjustable diameters. This has the advantage that the ring seal is subjected to less stress from relative movements between the annular rings of the hood and is only increased in diameter when the sealing effect is required.

[0025] It is advantageous if the ring seals are differentially pumped double ring seals. This has the advantage that any leaks can be compensated with low pumping power.

[0026] The vacuum-tight seal between the first and second circular rings of the hood's upper section can also be achieved using an elastically stretchable, vacuum-tight rubber sleeve. This is attached in a circular manner to the inside of the lower part of each of the two circular rings.

[0027] In order to improve the mechanical support of the hood parts or the circular rings against each other, it is advisable to arrange sliding bands made of abrasion-resistant high-temperature polymer, such as PEEK, in the hood parts or on the circular rings in the area above and / or below the ring seals.

[0028] It is advisable for the vacuum tank to have a volume approximately 5 to 10 times larger than the volume of the closed hood (including mold, container, green tire, and bladder). This ensures that a vacuum can be reliably generated within the hood. Furthermore, the time required to generate the necessary vacuum is significantly reduced. This can take place during the normal loading and unloading process.

[0029] With regard to the method using a heating press mentioned above, the invention is achieved by carrying out the following steps in succession: a) Loading the opened heating press by placing the green tire to be vulcanized into the container, with the second circular ring of the upper part of the hood being drawn in over the first circular ring on the outside. b) Moving the upper part of the heating press by the first partial stroke, pulling the second circular ring out towards the lower part of the heating press until it rests on the lower part of the heating press in order to obtain a closed interior of the hood, while the vulcanizing mold is only partially closed. c) Only in the case of ring seals consisting of a hose with an adjustable diameter: Inflating the circular ring-shaped hose seal to create a vacuum-tight seal on the hood. d) Opening the connection between the vacuum tank and the interior of the hood to create a partial vacuum in the vacuum-tight interior of the hood by equalizing the pressure between the vacuum tank and the interior of the hood. e) When the partial vacuum is maintained in the interior of the hood: Closing the connection between the vacuum tank and the hood.Opening the connection between the hood interior and the pump and pumping out the remaining air from the hood interior to create the vacuum f) Moving the heating press upper part around the second partial stroke, during which the second circular ring retracts over the first circular ring on the outside, so that the vulcanising mold is completely closed and then closing the connection between the hood interior and the pump g) Vulcanising the green tire and opening the connection between the pump and the vacuum tank and creating a vacuum in the vacuum tank, whereby the connection of the pump to the hood interior and the connection of the vacuum tank to the hood interior are each closed h) Opening the heating press and unloading the fully vulcanised tire and repeating steps a) - h) to vulcanise each additional tire.

[0030] The aforementioned process allows for time-efficient tire vulcanization. While the first tire is being vulcanized, the vacuum tank is already prepared to create the vacuum in the hood for the vulcanization of a second, subsequent tire, so that the hood can be brought into a vacuum within a very short time.

[0031] To facilitate step h), it is advantageous to first open another valve located in the hood to break the vacuum in the hood and then close it again.

[0032] An embodiment of a heating press and the method for vacuum vulcanization of a pneumatic vehicle tire, including further advantages, are shown in the following schematic Figures 1 to 4 described. They show: Fig. 1 shows a first embodiment of a heating press according to the invention with a container in the open state; Fig. 2 shows the heating press of the Fig. 1in the closing phase after a first partial stroke; Fig. 3 the heating press of the Fig. 1 and the Fig. 2 in closed state after a 2nd partial stroke; Fig. 4 a second embodiment of a heating press according to the invention with container in the open state;. Fig. 5 the heating press of the Fig. 4 in the closing phase after a first partial stroke; Fig. 6 the heating press of the Fig. 4 and the Fig. 5 in closed state after a 2nd partial stroke; Fig. 7 a third embodiment of a heating press according to the invention with container in the open state;. Fig. 8 the heating press of the Fig. 7 in the closing phase after a first partial stroke; Fig. 9 the heating press of the Fig. 7 and the Fig. 8 in closed state after a 2nd partial stroke; Fig. 10 a fourth embodiment of a heating press according to the invention with container in the open state;. Fig. 11 the heating press of the Fig. 10 in the closing phase after a first partial stroke;

[0033] The Fig. 1shows 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 inserted into the heating press 1.

[0034] The heating press 1 comprises an upper heating press part 3, which is connected to the hood upper part 4, and a lower heating press part 6, which is connected to the hood lower part 7 and has the corresponding mechanisms for positioning the tire to be vulcanized, for actuating the components of the vulcanization mold, for introducing the heating media, and for removing the fully vulcanized tire. The container 2 is enclosed by the two-part hood 4, 7 during the vulcanization process. 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 larger diameter than the first circular ring 23. The second circular ring 24 can be telescopically extended and retracted onto the first circular ring 23 in the 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 inner diameter and the same outer diameter and are arranged with their end faces flush in the heating press 1. The diameter of the second circular ring 24 of the hood upper part 4 is slightly larger than the diameter of the third circular ring 7 of the hood lower part.

[0035] A "center mechanism" 8 is arranged. This is also equipped with seals, where necessary, to create a vacuum seal between the center mechanism and the upper and lower sections of the heating press. A heating bladder (not shown) is attached to the center mechanism 8 and can be inserted into the green tire (not shown). Nozzles (not shown) are also arranged on the center mechanism 8 through which a heating medium can be introduced into the heating bladder (not shown).

[0036] The hood upper part 4 and the hood lower part 7 are designed to be airtight or vacuum-tight and, when closed, form a vacuum-tight hood interior 12. Ring seals 5, 9 are arranged for this purpose. An ring seal 9 is arranged between the first and second annulus 23, 24 for an airtight hood upper part 3 in a groove 25 arranged in the first annulus 23 and pointing towards the second annulus 24. Likewise, an annular seal 9 is arranged circumferentially on the outside of the third annulus 7 in a groove 25 corresponding to the groove 25 in the first annulus 23. Another horizontal ring seal 5 is arranged flush with the second annulus 24 in a groove 25 open towards the heating press upper part 3. The closed hood is thus designed to be airtight at the joints between the hood upper part 3 and the hood lower part 7 and between the first and second annulus 23, 24. The ring seal 5, 9 is a hose with an adjustable diameter.The diameter of the ring seal 5, 9 is slightly larger than the depth 27 of the groove 25.

[0037] A vacuum can be generated in the hood interior (= interior 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 12 of the hood, and wherein the vacuum tank 11 and the pump 10 are connected to one another. By creating a vacuum in the hood interior 12, particularly during the molding and vulcanization of the tire, the need for vent valves conventionally arranged in the molding surface of the vulcanizing mold is completely eliminated.

[0038] Container 2 is a conventional container 2 that is already known in the state of the art.

[0039] The container 2 contains the segmented vulcanizing mold with a lower heating plate 13, a lower side wall shell 14, an upper heating plate 15, an upper side wall shell 16, a lower bead ring 17 and an upper bead ring 18. Those components of the vulcanization mold that are moved in the vertical (= axial) direction (arrow P1) for opening and closing include the segment ring 19 consisting of seven to nine segment shoes 20 and the profile / mold segments 21 attached to it as well as the upper side wall shell 16 with the upper bead ring 18. The segment shoes 20 are moved apart radially in the direction of the arrow P2 for closing and opening the vulcanization mold.A locking ring 22 is arranged on the upper heating plate 15. The locking ring has a beveled inner surface that interacts with beveled outer surfaces of the segment shoes 20 of the segment ring 19 such that, when the vulcanization mold is closed, the segment shoes 20 are moved together in the radial direction to form the closed segment ring 19. The lower heating plate 13, the upper heating plate 15, and the locking ring 22 contain heating chambers into which at least one heating medium, in particular saturated steam (steam), is introduced to vulcanize the tire. In this way, the green tire (not shown) is heated from the outside via the segment shoes 20, the sidewall shells 14, 16, and the bead rings 17, 18, so that this heating is usually referred to as external heating.

[0040] A conventional heating bladder (not shown) is arranged in a known manner and is filled with at least one heating medium under pressure to center the green tire in the mold from the inside, whereby the heating bladder is formed into a torus shape appropriate for the tire. Since the green tire is heated from the inside via the heating bladder, this type of heating is referred to as internal heating.

[0041] In the Fig. 1 The heating press 1 is opened, with the second circular ring 24 of the hood upper part 3 telescopically retracted over the first circular ring 23. The green tire can be placed into the container 2.

[0042] In the Fig. 2 is the heating press 1 of the Fig. 1 shown in the closing phase after a first partial stroke TH 1.

[0043] The heating press upper part 3 is moved by the first partial stroke TH 1 and the second circular ring 24 is extended towards the heating press lower part 7 so that it rests on the heating press lower part 7 in the area of ​​the lying circular seal 5 and overlaps with the third circular ring 7 in the area of ​​the circular seal 9. The circular seal 9 seals the small gap 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 12 is maintained, while the vulcanization mold is only partially closed. In the case that the circular seals 5, 9 are a hose with an adjustable diameter, they are inflated to create a vacuum-tight seal between the hood 4, 7.The connection between vacuum tank 11 and hood interior 12 is opened to generate a partial vacuum in the vacuum-tight hood interior 12 by equalizing the pressure between vacuum tank 11 and hood interior 12. Upon maintaining the partial vacuum in the hood interior 12, the connection between vacuum tank 11 and hood 4, 7 is closed, the connection between hood interior 12 and pump 10 is opened, and the remaining air is pumped out of the hood interior 12 to generate the vacuum.

[0044] The Fig. 3 shows the heating press of the Fig. 1 and the Fig. 2 in closed state after a 2nd partial stroke TH 2 . After in the interior 12 of the closed hood 4, 7 of the Fig. 2a vacuum is generated, the airless vulcanizing mold is now completely closed and the connection between the vacuum tank 11 and the hood 4, 7 is closed by carrying out a second partial stroke TH 2 , in which the second circular ring 24 is drawn in on the outside over the first circular ring 23.

[0045] The connection between the hood interior 12 and the pump 10 is then closed. The green tire is vulcanized.

[0046] The sum of the 1st partial stroke TH1 and the 2nd partial stroke TH2 results in the total stroke GH. The tire is vulcanized. Vulcanizing a passenger car tire takes approximately 15 minutes. During this time, the connection between pump 10 and vacuum tank 11 is opened to create a vacuum in the vacuum tank 11, while the connection between pump 10 and hood 4, 7 and the connection between vacuum tank 11 and hood 4, 7 are both closed. After the tire has been vulcanized, the volume of the hood interior 12 is ventilated via a valve (not shown) and the heating press 1 is opened to unload the fully vulcanized tire from the container 2 containing the vulcanization mold. To do this, the hood upper part 4 first moves up, the second circular ring 24 is pulled in on the outside over the first circular ring 23, and the tread segments 21 are simultaneously moved outwards in the radial direction P2. The tire is released.

[0047] In the following further embodiments of a heating press 1 according to the invention, which are shown in the Figures 4 to 11 In the embodiments shown, almost all elements and functions are identical to those in the first embodiment. The only differences are in the size ratio 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, only 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 explained.

[0048] Therefore, only 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 are provided with reference symbols, as well as 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.

[0049] All other elements of the heating press are not explicitly provided with reference numerals and the means connected to the heating press for generating a vacuum in the interior of the hood of the heating press, such as pump 10, vacuum tank 11 and associated lines and valves, are shown in the Figures 4 to 11 not shown, even though they are present in the heating presses shown as well as in the Figures 1 to 3 shown. The elements of the heating press not provided with reference numerals and the means not shown for generating a vacuum in the interior of the hood of the heating press have already been described in connection with the first embodiment, as have their function and the overall functioning of a heating press according to the invention.

[0050] The Fig. 4shows 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 larger diameter than the first circular ring 23. The second circular ring 24 can be telescopically extended and retracted onto the first circular ring 23 in the 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.

[0051] The hood upper part 4 and the hood lower part 7 are designed to be airtight or vacuum-tight and, when closed, form a vacuum-tight hood interior 12. Ring seals 9 are arranged for this purpose. One ring seal 9 is arranged between the first and second circular rings 23, 24 for an airtight hood upper part 4 in a groove 25 arranged in the first circular ring 23 and pointing towards the second circular ring 24. Likewise, the third circular ring 23 has a circumferential vacuum-tight ring seal 9 at its upper end. Thus, the closed hood is designed to be airtight at the joints between the hood upper part 4 and the hood lower part 7 as well as between the first and second circular rings 23, 24. The ring seal 9 is a hose whose diameter can be adjusted. The diameter of the ring seal 9 is slightly larger than the depth 27 of the groove 25 in which it is arranged.

[0052] In the Fig. 5 is the heating press 1 of the Fig. 4 shown in the closing phase after a first partial stroke TH 1.

[0053] The heating press upper part 3 is moved by the first partial stroke TH 1 and the second circular ring 24 is extended towards the heating press lower part 7 so 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 seals 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 12 is maintained, while the vulcanization mold is only partially closed. In the case that the ring seals 9 are a hose with an adjustable diameter, they are inflated to create a vacuum-tight seal between the hood 4, 7.

[0054] The Fig. 6 shows the heating press of the Fig. 4 and the Fig. 5in closed state after a 2nd partial stroke TH 2 . After in the interior 12 of the closed hood 4, 7 of the Fig. 5 a vacuum is created, the airless vulcanizing mold is now completely closed by carrying out a second partial stroke TH 2 , in which the second circular ring 24 is drawn in on the outside over the first circular ring 23.

[0055] The Fig. 7shows 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 larger diameter than the first circular ring 23. The second circular ring 24 can be telescopically extended and retracted onto the first circular ring 23 in the 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 smaller than the diameter of the third circular ring 7 of the hood lower part.

[0056] The hood upper part 4 and the hood lower part 7 are designed to be airtight or vacuum-tight and, when closed, form a vacuum-tight hood interior 12. Ring seals 9 are arranged for this purpose. One ring seal 9 is arranged between the first and second annulus 23, 24 for an airtight hood upper part 4 in a groove 25 arranged in the first annulus 23 and pointing towards the second annulus 24. The third annulus 23 also has a vacuum-tight ring seal 9 running around its inner surface. Thus, the closed hood is designed to be airtight at the joints between the hood upper part 4 and the hood lower part 7 as well as between the first and second annulus 23, 24. The ring seal 9 is a hose whose diameter can be adjusted. The diameter of the ring seal 9 is slightly larger than the depth 27 of the groove 25 in which it is arranged.

[0057] In the Fig. 8 is the heating press 1 of the Fig. 7shown in the closing phase after a first partial stroke TH 1.

[0058] The heating press upper part 3 is moved by the first partial stroke TH 1 and the second circular ring 24 is extended towards the heating press lower part 7 so that it rests on the heating press lower part 7. The ring seal 9 on the inside of the third circular ring 7 then seals the small gap 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 12 is maintained, while the vulcanization mold is only partially closed. In the case that the ring seals 9 are a hose with an adjustable diameter, they are inflated to create a vacuum-tight seal between the hood 4, 7.

[0059] The Fig. 9 shows the heating press of the Fig. 7 and the Fig. 8in closed state after a 2nd partial stroke TH 2 . After in the interior 12 of the closed hood 4, 7 of the Fig. 8 a vacuum is created, the airless vulcanizing mold is now completely closed by carrying out a second partial stroke TH 2 , in which the second circular ring 24 is drawn in on the outside over the first circular ring 23.

[0060] The Fig. 10 shows a fourth embodiment of a heating press according to the invention with a container 2 in the open state. This embodiment differs from the previously described third embodiment only in that an elastically stretchable, vacuum-tight rubber sleeve 28 is provided as an additional vacuum-tight seal between the first circular ring 23 and the second circular ring 24 of the hood upper part. This is attached in a circular manner to the inside of the lower part of each of the two circular rings 23, 24.

[0061] In the Fig. 11 is the heating press 1 of the Fig. 10shown in the closing phase after a first partial stroke TH 1.

[0062] The heating press upper part 3 is moved by the first partial stroke TH 1 and the second circular ring 24 is extended toward the heating press lower part 7 so that it rests on the heating press lower part 7. This stretches the rubber sleeve 28, which is attached to both circular rings 23, 24, in the stroke direction. List of reference symbols (part of the description)

[0063] 1 Heating press 2 Container 3 Heating press upper part 4 Hood upper part 5 Ring seal 6 Heating press lower part 7 Hood lower part = third circular ring 8 Center mechanism 9 Ring seal 10 Pump 11 Vacuum tank 12 Interior of the hood 13 Lower heating plate 14 Lower side wall shell 15 Upper heating plate 16 Upper side wall shell 17 Lower bead ring 18 Upper bead ring 19 Segment ring 20 Segment shoe 21 Profile segment / mold segment 22 Locking ring 23 First circular ring 24 Second circular ring 25 Groove 26 Actuator 27 Depth of the groove 28 Rubber sleeve TH 1 1st partial stroke TH 2 2nd partial stroke GH Total stroke

Claims

1. 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 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 the heating press upper part (3) and the heating press lower part (6) are connected to the container (2) such that, when the heating press upper part (3) is being lowered through a total stroke (GH) that takes place in an axial direction (P1), during which total stroke the open end of the hood upper part (4) moves onto the heating press lower part (6), the mold parts (14, 16, 17, 18, 21) of the vulcanizing mold can be closed in the radial direction (P2), - 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 the total stroke (GH) can be traveled in a manner composed of a first partial stroke (TH1) and a second partial stroke (TH2), - wherein, after the first partial stroke (TH1), 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 (TH1), are provided, wherein the vacuum tank (11) and the pump (10) are connected to the interior space (12) of the hood (4, 7, 31), and wherein the vacuum tank (11) and the pump (10) are connected to one another, and - wherein, after the second partial stroke (TH2), 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).

2. Heating press (1) according to Claim 1, characterized in that 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), is provided.

3. Heating press (1) according to Claim 1 or 2, characterized in that 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).

4. Heating press (1) according to one or more of the preceding claims, characterized in that 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).

5. Heating press (1) according to Claim 4, characterized in that 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).

6. Heating press (1) according to Claim 4 or 5, characterized in that the ring seals (5, 9) consist of solid material.

7. Heating press (1) according to Claim 4 or 5, characterized in that the ring seals (5, 9) are hoses of variable diameter.

8. Heating press (1) according to one or more of Claims 4 to 7, characterized in that the ring seals (5, 9) are differentially inflated double ring seals.

9. Heating press (1) according to one or more of the preceding claims, characterized in that 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).

10. Heating press (1) according to one or more of the preceding claims, characterized in that the vacuum tank (11) has a volume that is approximately 5 to 10 times greater than the volume of the closed hoods (4, 7).

11. Method for vulcanizing a pneumatic vehicle tire under a vacuum in a heating press (1) according to one or more of Claims 1 to 10, characterized in that the following steps are performed in succession: 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.

12. Method for vulcanizing a pneumatic vehicle tire according to Claim 11, characterized in that, 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.