Bead forming component for a tire mold

Abstract

The application provides a bead forming part of a tire mold, comprising a top surface for supporting a curing bladder, a bead forming surface for forming a bead portion, and an overflow exhaust structure, wherein the overflow exhaust structure comprises an exhaust groove on the top surface, the exhaust groove is connected to the bead forming surface, and the exhaust groove is in communication with the outside of the mold; the cross section of the exhaust groove comprises a first exhaust area and a second exhaust area; the first exhaust area is located axially inside the second exhaust area, and the cross section width of the second exhaust area gradually decreases in the direction from the axially inside to the axially outside. The tire mold structure with the above technical solution not only ensures that the overflow exhaust structure has good exhaust performance, but also inhibits the formation of obvious rubber strips on the toe of the tire lip, so that the finished tire has a good visual appearance.

Description

Technical Field

[0001] This invention relates to the field of tire manufacturing, and more particularly to a bead forming component for a tire mold. Background Technology

[0002] In tire manufacturing, different mold components are used to form different parts of the tire. For example, the mold tread ring is used to form the tire tread pattern, the upper and lower cavities of the mold form the upper and lower sidewalls of the tire, and the mold bead ring is used to form the tire bead area. Because the tire bead area has bead wires and the bead area is relatively rigid, the air venting performance of the bead area lags behind other parts of the tire.

[0003] To ensure proper venting at the bead area, venting elements are typically installed at the bead area of ​​the mold. For example, a circumferential venting line is provided at the bead heel forming area of ​​the mold; several venting holes are spaced apart on the circumferential venting line; and a venting groove is provided at the bead toe forming area of ​​the mold, so that gas can be discharged from the mold cavity through the venting elements during tire formation, thus ensuring tire quality.

[0004] Current molds typically have several venting grooves on the circumferential direction of the top surface of the tire bead ring component near the tire bead toe. The venting grooves have a square cross-section. The top surface of the tire bead ring component also has at least one annular groove, and the bottom of the annular groove has several axially extending venting holes. During tire forming, the gas in the bead area can flow through the venting grooves at the tire bead toe and then through the venting holes at the bottom of the annular groove, thereby being discharged outside the mold.

[0005] During tire forming, the rubber material in the tire bead area is subjected to intense compression and airflow, causing a small amount of rubber to enter the venting grooves on the top surface of the bead ring component. This results in a rubber strip remaining at the bead toe of the finished tire. This rubber strip at the bead toe can easily get stuck in the rim's sealing area when the tire is fitted to the rim, leading to poor tire airtightness. Furthermore, the presence of residual rubber strips in the tire bead area creates a visually unappealing appearance. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a tire bead forming component for a tire mold.

[0007] To address the aforementioned technical problems, this invention provides a tire bead forming component for a tire mold, comprising a top surface, a bead forming surface, and an overflow venting structure. The top surface supports the vulcanizing bladder, and the bead forming surface forms the bead portion. The overflow venting structure includes a venting groove located on the top surface and connected to the bead forming surface, communicating with the outside of the mold. The cross-section of the venting groove includes a first venting area and a second venting area. The first venting area is located axially inside the second venting area, and the cross-sectional width of the second venting area gradually decreases from the axially inside to the axially outside direction.

[0008] In a preferred embodiment, the cross-sectional width of the first exhaust zone is greater than the maximum cross-sectional width of the second exhaust zone.

[0009] In a preferred embodiment, the maximum cross-sectional width of the second exhaust zone is 0.4-0.6 times the cross-sectional width of the first exhaust zone.

[0010] In a preferred embodiment, the cross-sectional depth of the first exhaust zone is greater than or equal to the cross-sectional depth of the second exhaust zone.

[0011] In a preferred embodiment, the cross-sectional depth of the second exhaust zone is 0.3-0.5 times the cross-sectional depth of the exhaust groove.

[0012] In a preferred embodiment, the cross-sectional width of the first exhaust zone remains constant in the direction from the axial inner side to the axial outer side.

[0013] In a preferred embodiment, the cross-sectional profile of the second exhaust zone is triangular, V-shaped, trapezoidal, or arc-shaped.

[0014] In a preferred embodiment, the maximum cross-sectional width of the second exhaust zone is 0.8mm-1.2mm; the cross-sectional depth of the second exhaust zone is 0.4mm-0.6mm.

[0015] In a preferred embodiment, the cross-sectional area of ​​the second exhaust zone accounts for 0.2-0.5 of the cross-sectional area of ​​the exhaust channel.

[0016] In a preferred embodiment, the overflow venting structure further includes an annular groove and a plurality of vent holes, the annular groove extending circumferentially along the top surface of the bead forming portion;

[0017] The overflow venting structure includes multiple venting grooves, one end of which is connected to the tire bead forming surface and the other end is connected to the annular groove. The multiple venting holes are connected between the annular groove and the outside of the mold.

[0018] The plurality of venting grooves are evenly spaced along the circumference of the bead forming surface, and the number of the plurality of venting grooves is 12-18.

[0019] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0020] During tire forming, the rubber in the bead area is subjected to strong compression accompanied by airflow. Air in the vicinity of the bead forming component flows normally through the first venting zone of the overflow venting structure, passing through the venting holes at the bottom of the annular groove to vent outside the mold. Simultaneously, a small portion of rubber, compressed and flowing with the air, enters the second venting zone (narrower at the bottom and wider at the top) on the axial outer side of the venting groove. This hindrance prevents the rubber from flowing rapidly, ultimately forming tiny rubber strips at the bead of the finished tire. Because these tiny rubber strips remaining at the bead are extremely short, all less than 1mm in length, they do not get trapped in the airtight area of ​​the rim during tire assembly, thus ensuring good airtightness and a pleasing appearance. Therefore, the tire mold structure employing the above technical solution ensures good venting performance of the overflow venting structure while suppressing the formation of obvious rubber strips at the bead, resulting in a tire with a good visual appearance. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of the bead forming component of the tire mold of the present invention;

[0022] Figure 2 for Figure 1 A schematic diagram of an embodiment of the A-A' cross-sectional structure;

[0023] Figure 3 for Figure 1 A schematic diagram of another embodiment of the A-A' cross-sectional structure;

[0024] Figure 4 for Figure 1 A schematic diagram of another embodiment of the A-A' cross-sectional structure. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] To clearly describe the mold structure of the tire of the present invention, the orientation of the tire is first defined. The tire has a center of rotation and an equatorial plane CL. The direction around the center of rotation of the tire is defined as the tire circumferential direction. The direction parallel to the center of rotation of the tire along the width of the tire cross section is defined as the tire axial direction. The direction perpendicular to the center of rotation of the tire along the height of the tire cross section is defined as the tire radial direction. The orientation definition of the tire mold is the same as that of the tire.

[0027] Figures 1-2 This diagram illustrates a cross-sectional view of a bead forming component of a tire mold according to the present invention. The bead forming component is generally detachably connected to the sidewall forming component of the tire mold. The bead forming component has a top surface 1 and a bottom surface 2. The top surface 1 typically serves as a support surface for the vulcanizing bladder and cooperates with a vulcanizing bladder holder to fix the vulcanizing bladder. The bottom surface 2 primarily mates with the body of the tire mold. The bead forming component also has a bead forming surface 3 and a side slope 4. The side slope 4 primarily mates with the sidewall forming component of the tire mold. The bead forming surface 3 is used to form the bead portion, and it has a toe forming portion 31 and a heel forming portion 32. The bead forming surface 3 and the vulcanizing bladder (i.e., the vulcanizing air bladder, a conventional component, will not be described further here) work together to form the bead portion under certain conditions.

[0028] The top surface 1 of the bead forming component is provided with an overflow venting structure, which includes a venting groove 11 and at least one annular groove 12. One end of the venting groove 11 extends to the bead forming portion 31 connected to the bead forming surface 3, and the other end extends to the annular groove 12. Multiple venting holes 13 are provided at the bottom of the annular groove 12, extending to the bottom surface 2 of the bead forming component. During vulcanization, gas from the bead portion can enter the annular groove 12 from the area where the bead forming portion 31 is located through the venting groove 11 of the overflow venting structure and finally exit the mold through the venting holes 13.

[0029] In this embodiment, the cross-section of the venting groove 11 on the top surface 1 of the bead forming component includes two venting areas, namely, the first venting area 11a and the second venting area 11b of the venting groove 11. Specifically, as follows... Figure 2 As shown, Figure 2 for Figure 1 A schematic diagram of an embodiment of the A-A' cross-sectional structure, wherein the first exhaust region 11a is located axially inside the second exhaust region 11b. The cross-sectional width of the first exhaust region 11a remains constant along the axially inner direction pointing outward. Specifically, the cross-sectional profile of the first exhaust region 11a preferably adopts a regular quadrilateral shape, such as... Figure 2 The rectangle shown has a constant cross-sectional width. The cross-sectional width of the second exhaust zone 11b gradually decreases in the direction from the inner side to the outer side of the axial direction. Specifically, the cross-sectional profile of the second exhaust zone 11b can be triangular or V-shaped, or it can be trapezoidal or arc-shaped. Figure 2The cross-sectional profile of the second venting zone 11b shown is triangular. The venting groove 11 of the bead forming component is provided with a first venting zone 11a and a second venting zone 11b. During tire forming, the rubber at the bead area is subjected to strong compression accompanied by airflow. Gas near the bead forming component flows through the first venting zone 11a of the venting groove 11 and exits the mold through the venting hole 13 at the bottom of the annular groove 12. Simultaneously, a small portion of rubber, due to the compression of the vulcanizing bladder and airflow, enters the second venting zone 11b on the axial outer side of the venting groove 11, where it is obstructed and unable to flow rapidly. Ultimately, a tiny rubber strip forms at the bead toe of the finished tire, or even none at all. Because the remaining tiny rubber strip at the bead toe is extremely short, the tire will not be sandwiched in the rim's airtight area during assembly, ensuring good airtightness of the tire, while also maintaining a good visual appearance.

[0030] To ensure good venting performance of the bead forming component while avoiding the formation of long rubber strips, the cross-sectional area of ​​the second venting zone 11b of the overflow venting structure should ideally be 0.2-0.5 times the cross-sectional area of ​​the venting channel 11. If the cross-sectional area of ​​the second venting zone 11b of the venting channel 11 is too large, during the tire vulcanization process, the rubber, under strong compression, will easily enter the first venting zone 11a and the second venting zone 11b of the venting channel 11 with the airflow, easily forming obvious rubber strips at the bead of the finished tire, affecting the visual appearance of the finished tire; at the same time, it may easily lead to poor tire air tightness in the rim airtight area during tire assembly. Conversely, if the cross-sectional area of ​​the second venting zone 11b of the venting channel 11 is too small, the overall venting space of the venting channel 11 will be insufficient, thus affecting the venting effect of the bead forming component of the mold, and easily causing appearance defects in the bead area of ​​the finished tire.

[0031] The cross-sectional width of the second exhaust region 11b gradually decreases along the axial inward direction towards the axial outward direction, exhibiting a cross-sectional profile that is wider at the top and narrower at the bottom. Furthermore, the cross-sectional width of the first exhaust region 11a is greater than the maximum cross-sectional width of the second exhaust region 11b. For example... Figure 2The cross-sectional profile of the second exhaust region 11b is a triangle or a V-shaped profile, wider at the top and narrower at the bottom. The upper width C of the second exhaust region 11b (i.e., its maximum cross-sectional width) is (0.4-0.6) times the width B of the first exhaust region 11a (i.e., its cross-sectional width). The cross-sectional depth of the first exhaust region 11a is greater than or equal to the cross-sectional depth of the second exhaust region 11b; specifically, the depth E of the second exhaust region 11b is (0.3-0.5) times the depth D of the exhaust groove 11. By setting the second venting zone 11b of the venting groove 11 to a cross-sectional profile that is wider at the top and narrower at the bottom, and optimizing the width and depth of the second venting zone 11b, the second venting zone 11b presents a semi-closed venting channel during vulcanization. Compared with the open venting channel of the regularly shaped first venting zone 11a, a small portion of the rubber compound will be obstructed when flowing through the narrow second venting zone 11b during extrusion and airflow, and will not be able to flow in quickly. Therefore, a very small rubber strip is formed in this area, and the length of the rubber strip is less than 1 mm. There will not even be any rubber strip left on the tire bead. Meanwhile, the first venting zone 11a located on the axial inner side can maintain normal venting effect.

[0032] In this embodiment, the upper width C of the second exhaust zone 11b of the exhaust groove 11 is preferably 0.8mm-1.2mm; the depth E of the second exhaust zone 11b is preferably 0.4mm-0.6mm.

[0033] To further ensure the venting effect of the mold bead forming component, the venting grooves 11 of the overflow venting structure are evenly distributed in 12-18 venting grooves in the circumferential direction of the top surface 1.

[0034] Figure 3 for Figure 1 A schematic diagram of another embodiment of the A-A' cross-sectional structure, and... Figure 2 The difference in the overflow exhaust structure shown is that the axial cross-section of the second exhaust area 11b is trapezoidal, and the lower width F of the second exhaust area 11b is preferably (0.2-0.3) of the upper width C. In this way, the second exhaust area 11b of the exhaust groove 11 still presents a cross-sectional profile that is wider at the top and narrower at the bottom, which ensures the exhaust effect of the exhaust groove 11 while avoiding the formation of a long rubber strip on the tire bead.

[0035] Figure 4 for Figure 1 A schematic diagram of another embodiment of the A-A' cross-sectional structure; and Figure 2The difference in the overflow exhaust structure shown is that the axial cross-section of the second exhaust area 11b is arc-shaped, and the depth E of the second exhaust area 11b is preferably 0.4mm-0.6mm. In this way, the second exhaust area 11b of the exhaust groove 11 still presents a cross-sectional profile that is wider at the top and narrower at the bottom, which ensures the exhaust effect of the exhaust groove 11 while avoiding the formation of a long rubber strip on the tire bead.

[0036] The venting groove 11 of the overflow venting structure on the top surface 1 of the molded tire bead forming component described above has two venting areas, namely the first venting area 11a and the second venting area 11b of the venting groove 11. The second venting area 11b of the venting groove 11 has a cross-sectional profile that is wider at the top and narrower at the bottom. The molded tire bead forming component was prototyped and applied to the production of 10 spare tires of the T165 / 80D17 specification. By comparing the tires produced using conventional molded tire bead forming components and the tires produced using the molded tire bead forming component of this invention, after assembly with the rim, water leakage tests were conducted according to standard test conditions. The comparison results are as follows:

[0037] Test time / minute Test Results Test judgment Previous embodiments 5 Bubbling Unqualified Example of this case 5 No bubbles qualified

[0038] Through the above comparative tests, it is found that tires produced using the bead forming component of this case are beneficial to improving air tightness; at the same time, the rubber strip at the bead of the finished tire is extremely small, and the tire has a good visual appearance.

[0039] The above description is merely a preferred embodiment of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention by those skilled in the art within the scope of the technology disclosed in the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A tire bead forming component for a tire mold, comprising a top surface, a bead forming surface, and an overflow venting structure, wherein the top surface supports a vulcanizing bladder, and the bead forming surface forms the bead portion; the overflow venting structure includes a venting groove located on the top surface, connected to the bead forming surface, and communicating with the outside of the mold; characterized in that, in, The same cross-section of the exhaust channel includes a first exhaust region and a second exhaust region; the first exhaust region is located axially inside the second exhaust region, and the cross-sectional width of the second exhaust region gradually decreases along the axial inward direction to the axial outward direction; the cross-sectional profile of the second exhaust region is triangular, V-shaped, trapezoidal, or arc-shaped; wherein, the same cross-section of the exhaust channel is the cross-section in its width direction; the cross-sectional width of the first exhaust region is greater than the maximum cross-sectional width of the second exhaust region; the cross-sectional depth of the first exhaust region is greater than or equal to the cross-sectional depth of the second exhaust region; the cross-sectional width of the first exhaust region remains unchanged along the axial inward direction to the axial outward direction.

2. The tire bead forming component of a tire mold as described in claim 1, characterized in that: The maximum cross-sectional width of the second exhaust zone is 0.4-0.6 times the cross-sectional width of the first exhaust zone.

3. The tire bead forming component of a tire mold as described in claim 1, characterized in that: The cross-sectional depth of the second exhaust zone is 0.3-0.5 times the cross-sectional depth of the exhaust groove.

4. The tire bead forming component of a tire mold as described in claim 1, characterized in that: The maximum cross-sectional width of the second exhaust zone is 0.8mm-1.2mm; the cross-sectional depth of the second exhaust zone is 0.4mm-0.6mm.

5. The tire bead forming component of a tire mold as described in claim 1, characterized in that: The cross-sectional area of ​​the second exhaust zone accounts for 0.2-0.5 of the cross-sectional area of ​​the exhaust channel.

6. The tire bead forming component of a tire mold as described in claim 1, characterized in that: The overflow venting structure also includes an annular groove and multiple vent holes, the annular groove extending circumferentially along the top surface of the bead forming portion; The overflow venting structure includes multiple venting grooves, one end of which is connected to the tire bead forming surface and the other end is connected to the annular groove. The multiple venting holes are connected between the annular groove and the outside of the mold. The plurality of venting grooves are evenly spaced along the circumference of the bead forming surface, and the number of the plurality of venting grooves is 12-18.

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