Method and apparatus for the production of a prevulcanized tread, tread and retreaded vehicle tires

Abstract

The present invention relates to a method and an apparatus for producing a pre-vulcanized tread. In a first step, a tread is formed (S1). The formed tread is pre-vulcanized (S2). Subsequently, the pre-vulcanized tread is slowly cooled in a preheated environment (S3). After slow cooling (S3), the pre-vulcanized tread can be deburred or trimmed (S4). The invention also relates to a tread produced by such a method or apparatus, and to a retreaded vehicle tire with such a tread.

Description

[0001] The present invention relates to a method and a device for producing a pre-vulcanized tread. The invention further relates to a tread produced by such a method or device, and to a retreaded vehicle tire with such a tread.

[0002] Retreaded tires are less expensive to manufacture than new tires and are frequently used, especially in the commercial vehicle sector. To manufacture a retreaded tire, the tread of a used tire is removed, and in subsequent steps, a new tread with a tire profile is applied and vulcanized onto it.

[0003] A method for manufacturing a retreaded vehicle tire is known, for example, from DE 10 2017 211 759 A1. This method uses a cold process in which profiled treads are bonded to tire carcasses from which the worn treads have been removed. The bond between the tire carcass and the tread is achieved via a bonding rubber layer. Vulcanizing presses are used to manufacture the treads; each press is equipped with a number of heated molds that, during the pressing and pre-vulcanization process, create a tire tread pattern in the tread.

[0004] From DE 10 2010 020 060 A1, a vulcanizing press system for the production of treads for tire retreading is known. This system has a press frame with one or more press levels in which treads with a tire profile are pressed from strips of raw rubber.

[0005] It is an object of the present invention to provide a tread with improved properties and a retreaded vehicle tire with such a tread, as well as a method and a device for manufacturing the tread.

[0006] This problem is solved by a method having the features of claim 1, a device having the features of claim 6, a tread according to claim 9 and a retreaded vehicle tire according to claim 10.

[0007] Preferred embodiments of the invention are the subject of the dependent claims.

[0008] According to a first aspect of the invention, a method for producing a pre-vulcanized tread for retreading a vehicle tire comprises the steps: - Shapes of a running track; - Pre-vulcanizing the molded tread; and - slow cooling of the prevulcanized tread in a preheated environment.

[0009] In the inventive method, the pre-vulcanized tread is slowly cooled in a preheated environment. This slow cooling results in more energy remaining in the tread. This, in turn, leads to improved braking performance of the retreaded tire on wet roads and improved rolling resistance.

[0010] According to one aspect of the invention, the prevulcanized tread strip is placed in a preheated chamber or transported through a preheated tunnel for slow cooling. In the preheated chamber, the prevulcanized tread strip can be stored until the desired cooling level is reached. It must then be removed from the chamber. Alternatively, the tread strip can be transported through a preheated tunnel. The transport speed is selected so that the desired cooling level is reached upon exiting the tunnel.

[0011] According to one aspect of the invention, the preheated environment is preheated with waste heat generated during pre-vulcanization. In this way, the waste heat that would otherwise be generated can be put to additional use, thus increasing the energy efficiency of the manufacturing process.

[0012] According to one aspect of the invention, the forming of the tread and the pre-vulcanization of the formed tread are carried out in a press mold. Such press molds are already used for this purpose and are therefore available from various manufacturers, so that no costly custom-made products are required.

[0013] According to one aspect of the invention, the pre-vulcanized tread strip is deburred or trimmed after slow cooling. This allows the removal of any excess material, etc., resulting from the forming process.

[0014] According to another aspect of the invention, a device for producing a pre-vulcanized tread for retreading a vehicle tire comprises: - a press mold for forming a tread and for pre-vulcanizing the formed tread; and - a preheated chamber or tunnel for the slow cooling of the prevulcanized tread.

[0015] In the device according to the invention, a press mold in which the tread is formed and pre-vulcanized is supplemented by a preheatable chamber or tunnel. The pre-vulcanized tread is slowly cooled in the chamber or tunnel. This slow cooling results in more energy remaining in the tread. This, in turn, leads to improved braking performance of the retreaded tire on wet roads and improved rolling resistance.

[0016] According to one aspect of the invention, the preheated chamber or tunnel is preheated using waste heat generated during pre-vulcanization. In this way, the waste heat that would otherwise be generated can be put to additional use, thus increasing the energy efficiency of the device.

[0017] According to one aspect of the invention, the device includes a cutting device for deburring or trimming the pre-vulcanized tread strip after slow cooling. Such a cutting device allows the removal of excess material, etc., from the tread strip resulting from the forming process.

[0018] According to one aspect of the invention, a tread strip is produced using a method or device according to the invention.

[0019] According to one aspect of the invention, a retreaded vehicle tire has a tread according to the invention. Such a retreaded vehicle tire is characterized by improved braking performance on wet roads and improved rolling resistance.

[0020] Further features of the present invention will become apparent from the following description and the attached claims in conjunction with the figures. Figure overview Fig. Figure 1 schematically shows a pre-vulcanized tread for the cold retreading of a vehicle tire; Fig. Figure 2 schematically shows a section of a cold-retreaded vehicle tire; Fig. Figure 3 shows a method for producing a prevulcanized tread; Fig. Figure 4 schematically shows a first embodiment of a device for producing a pre-vulcanized tread strip; and Fig. Figure 5 schematically shows a second embodiment of a device for producing a pre-vulcanized tread. Character description

[0021] To better understand the principles of the present invention, embodiments of the invention are explained in more detail below with reference to the figures. The same reference numerals are used in the figures for identical or equivalently acting elements and are not necessarily described again for each figure. It is understood that the invention is not limited to the embodiments shown and that the described features can also be combined or modified without departing from the scope of protection of the invention as defined in the appended claims.

[0022] Fig. Figure 1 schematically shows a pre-vulcanized tread 2 for the cold retreading of a vehicle tire. The tread 2 has a profiled upper surface 3 and a corresponding lower surface 4, which is bonded to a tire carcass during cold retreading.

[0023] Fig. Figure 2 schematically shows a section of a cold-retreaded vehicle tire 1. On the upper side of a carcass 5 is a tire belt with a first belt layer 6 and a second belt layer 7. The tire belt is covered by a bandage 8. The tread 2 is arranged on the upper side of the bandage 8.

[0024] Fig. Figure 3 shows a method for producing a pre-vulcanized tread. In a first step, a tread is formed S1. The formed tread is then pre-vulcanized S2. The forming S1 and pre-vulcanization S2 of the formed tread can, for example, be carried out in a press mold. Subsequently, the pre-vulcanized tread is slowly cooled S3 in a preheated environment. For this purpose, the pre-vulcanized tread can, for example, be placed in a preheated chamber or transported through a preheated tunnel. Preferably, the preheated environment is preheated with waste heat generated during pre-vulcanization S2. After slow cooling S3, the pre-vulcanized tread can be deburred or trimmed S4.

[0025] Fig. Figure 4 schematically shows a first embodiment of a device 10 for producing a pre-vulcanized tread. The device 10 has a press mold 11 in which a tread is formed and pre-vulcanized. The pre-vulcanized tread is removed from the press mold 11 by a transfer unit 12, shown here as a robot, and placed into a preheated environment 13. This step can alternatively be performed manually. In this embodiment, the preheated environment 13 is a preheated chamber 130. The tread is stored in the chamber 130 until the desired cooling of the tread is achieved. The transfer unit 12 then removes the tread from the chamber 130 and feeds it to a cutting device 14. After slow cooling, the pre-vulcanized tread is deburred or trimmed by the cutting device 14.In this way, excess material etc. resulting from the forming process of the tread strip can be removed. In this embodiment, chamber 130 is preheated with waste heat generated during pre-vulcanization in the press mold 11. This is shown in . Fig. 4 indicated by a connecting tube 15 between the press mold 11 and the chamber 130.

[0026] Fig. Figure 5 schematically shows a second embodiment of a device 10 for producing a pre-vulcanized tread. This embodiment largely corresponds to the one in Fig.In the embodiment shown in Figure 4, however, instead of a preheated chamber, a preheated tunnel 131 is used into which the tread is inserted by a first transfer unit 12. During transport through the tunnel 131, the tread cools down. The transport speed is selected such that the desired cooling is achieved when the tread exits the tunnel 131. The cooled tread is received by a second transfer unit 12' at the end of the tunnel 131 and fed to a cutting device 14. Depending on the design of the device 10, instead of a first and a second transfer unit 12, 12', only a single transfer unit 12 may be provided, e.g., because individual steps are performed manually or the transfer unit 12 can perform both the insertion of the tread into the tunnel 131 and its receipt at the end of the tunnel 131. Reference symbol list 1 vehicle tire 2 treads 3 Top 4 Underside 5 Carcass 6 First belt layer 7 Second belt layer 8 Bandage 10 Device 11 Press mold 12, 12' Transfer unit 13 Preheated environment 130 Chamber 131 tunnels 14 Cutting device 15 Connecting pipe S1 Forms of a tread pattern S2 Pre-vulcanizing the tread S3 Slow cooling of the pre-vulcanized tread S4 Deburring or trimming the prevulcanized tread QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2017 211 759 A1

[0003] DE 10 2010 020 060 A1

[0004]

Claims

[1] Method for producing a prevulcanized tread (2) for retreading a vehicle tire (1), comprising the steps: - Shapes (S1) of a running track (2); - Pre-vulcanizing (S2) of the formed tread (2); and - slow cooling (S3) of the prevulcanized tread (2) in a preheated environment (13). [2] Method according to claim 1, wherein the prevulcanized tread (2) is placed in a preheated chamber (130) for slow cooling (S3) or transported through a preheated tunnel (131). [3] Method according to claim 1 or 2, wherein the preheated environment (13) is preheated with waste heat generated during prevulcanization (S2). [4] Method according to one of the preceding claims, wherein the forming (S1) of the tread (2) and the prevulcanizing (S2) of the formed tread (2) are carried out in a press mold (11). [5] Method according to one of the preceding claims, wherein the prevulcanized tread (2) is deburred or trimmed (S4) after slow cooling (S3). [6] Device (10) for producing a pre-vulcanized tread (2) for retreading a vehicle tire (1), comprising: - a press mold (11) for forming (S1) a tread strip (2) and for pre-vulcanizing (S2) the formed tread strip (2); and - a preheated chamber (130) or a preheated tunnel (131) for slow cooling (S3) of the prevulcanized tread (2). [7] Device (10) according to claim 6, wherein the preheated chamber (130) or the preheated tunnel (131) is preheated with waste heat generated during prevulcanization (S2). [8] Device (10) according to claim 6 or 7, comprising a cutting device (14) for deburring or trimming (S4) the prevulcanized tread (2) after slow cooling (S3). [9] Running strip (2), wherein the running strip (2) is produced by a method according to any one of claims 1 to 5 or by a device (10) according to any one of claims 6 to 8. [10] Retreaded vehicle tire (1) with a tread (2) according to claim 9.

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