Manufacturing method of pneumatic tire

Abstract

To provide a manufacturing method of a pneumatic tire capable of removing a spew accurately.SOLUTION: A manufacturing method of a pneumatic tire includes a trimming step of trimming a spew of a pneumatic tire, the trimming step including: an accommodation process of accommodating at least a part of an inflating body capable of inflating by being supplied with a fluid inward the tire; a supporting process of causing the inflating body inflated to support an inner surface of the tire; and a removing process of removing with a cutter blade the spew of the tire supported by the inflating body.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a method of manufacturing a pneumatic tire that includes a trimming step of trimming a spew of the pneumatic tire. [Background technology]

[0002] A large number of rubber projections called spews are formed on the outer surface of a vulcanized tire. The spews are removed using a trimming device or the like. Patent Document 1 discloses a trimming device that rotates a tire in an upright position and removes the spews with a cutter blade.

[0003] In recent years, the weight of tires has been reduced due to the trend toward lower fuel consumption, and the rigidity of tires has been declining. Therefore, when using the trimming device described above, depending on the rigidity of the tire, the tire may vibrate vertically or horizontally, which may change the gap between the cutter blade and the outer surface of the tire, making it difficult to remove the spew with precision. In addition, there is a risk that the cutter blade may come into contact with the tire and scratch the outer surface of the tire.

[0004] There is a method of mounting a tire on a rim and trimming the spew (for example, as disclosed in the prior art of Patent Document 2), but it takes a lot of work to remove and attach the rim, and it is necessary to prepare multiple types of rims according to tire sizes. Also, depending on the trimming device, it may be necessary to add a rim rotation device, etc. As such, there are various issues with the method of mounting a tire on a rim and trimming the spew. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-227069 [Patent Document 2] Special Publication No. 8-9207 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a method for manufacturing a pneumatic tire that is capable of removing spew with high accuracy. [Means for solving the problem]

[0007] The manufacturing method of a pneumatic tire disclosed herein includes a trimming step of trimming a spew of a pneumatic tire, the trimming step including a accommodating step of accommodating inside the tire at least a portion of an inflatable body that can be inflated by supplying a fluid, a supporting step of supporting an inner surface of the tire with the inflated inflatable body, and a removing step of removing the spew of the tire supported by the inflatable body with a cutter blade. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a side view illustrating an example of a trimming device. [Diagram 2] Cross-sectional view of line II-II in Figure 1 [Diagram 3] A flow chart showing an example of a spew trimming process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Trimming device] First, an example of the configuration of a trimming device 1 used in manufacturing a pneumatic tire T will be described with reference to Figs. 1 and 2. Note that in each drawing, the dimensional ratios in the drawing do not necessarily match the actual dimensional ratios, and the dimensional ratios between the drawings do not necessarily match either. Fig. 1 is a side view showing a schematic diagram of an example of the trimming device 1. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. In Fig. 2, only the external appearances of a tread-side removal mechanism 10 and a valve 16, which will be described later, are shown in a schematic diagram. Also, the cross section of the pneumatic tire T in Fig. 2 is not hatched.

[0010] As shown in Fig. 1, the trimming device 1 is a device that rotates a pneumatic tire T (hereinafter simply referred to as "tire T") to remove spew Sp formed on the outer surface of the tire T. The tire T is a tubeless tire, and an inner liner IL (see Fig. 2) is provided on the innermost surface of the tire T. The inner liner IL is made of rubber with low air permeability.

[0011] The trimming device 1 is preferably configured to rotate the tire T in an upright state. This allows the number of parts to be reduced and the time required to remove the spew Sp to be shortened compared to a trimming device that rotates the tire T in a flat (lying) state. This is because rotating the tire T in a flat state requires a process of lifting the tire T from the conveying path. Note that the trimming device 1 is not limited to the above, and may be configured to rotate the tire T in a flat state.

[0012] The trimming device 1 includes a rotation mechanism 2 that supports and rotates a tire T. The rotation mechanism 2 includes a plurality of rollers 3a to 3c for rotating the tire T, and a rotation drive member 4 that drives and rotates at least one of the plurality of rollers 3a to 3c.

[0013] The rollers 3a to 3c are provided to support a tire T. A position of the tire T supported by the rollers 3a to 3c is defined as a support position X1. FIG 1 shows an example in which one upper roller 3a is provided above the tire T at the support position X1, and two lower rollers 3b, 3c are provided below the tire T.

[0014] The upper roller 3a can be moved up and down by a roller moving mechanism 17. The upper roller 3a preferably has a shape in which the diameter of its roller shaft is reduced from the outer side toward the center. This makes it possible to regulate the movement of the tire T in the axial direction AD (see FIG. 2). The rotation drive member 4 is, for example, an electric motor. FIG. 1 shows an example in which the rotation drive member 4 is provided on the lower roller 3b on the upstream side (the right side of FIG. 1).

[0015] The trimming device 1 includes an input path 5 for carrying the tire T to the support position X1, an output path 6 for carrying the tire T from the support position X1, and an output member 7 for carrying the tire T from the support position X1. The input path 5 is provided upstream of the lower roller 3b (to the right in FIG. 1), and the output path 6 is provided downstream of the lower roller 3c (to the left in FIG. 1).

[0016] It is preferable that the carry-in path 5 and the carry-out path 6 are inclined downward toward the downstream side (the left side in FIG. 1). This allows the tire T to roll on the carry-in path 5 and the carry-out path 6 by its own weight, making it easier to transport the tire T downstream.

[0017] The discharge member 7 is, for example, a push-out member that pushes out the tire T from the support position X1. The discharge member 7 is, for example, disposed between the carry-in path 5 and the lower roller 3b. The discharge member 7 is, for example, a cylinder.

[0018] The trimming apparatus 1 includes an entrance path opening / closing mechanism 8 provided upstream of the entrance path 5 (on the right side in FIG. 1), and an exit path opening / closing mechanism 9 provided downstream of the exit path 6 (on the left side in FIG. 1). The opening / closing mechanisms 8, 9 are configured to open and close in the vertical direction, for example. Providing the entrance path opening / closing mechanism 8 can prevent other tires from entering the trimming apparatus 1 when removing the spew Sp of the tire T. Providing the opening / closing mechanisms 8, 9 can also prevent the spew Sp removed from the tire T from scattering.

[0019] The trimming device 1 includes, for example, a tread-side removing mechanism 10 that removes the spew Sp formed in the tread Tr of the tire T, and a sidewall-side removing mechanism 11 that removes the spew Sp formed in the sidewall Sw of the tire T. Note that the trimming device 1 may remove the spew Sp formed in the tread Tr and the sidewall Sw with one removing mechanism.

[0020] 1 shows an example in which the tread-side removal mechanism 10 is provided above the tire T at the support position X1 and downstream of the upper roller 3a, and the sidewall-side removal mechanism 11 is provided on the lower side of the tire T at the support position X1 and between the two lower rollers 3b, 3c. In this example, although not shown in FIG. 1, two sidewall-side removal mechanisms 11 are provided to sandwich the tire T. The removal mechanisms 10, 11 may be configured to be able to swing the cutter blade 12 along the shape of the tire T.

[0021] As shown in Figs. 1 and 2, the tread-side removal mechanism 10 includes a cutter blade 12 for removing the spew Sp, and a tread-side arm 13 for moving the cutter blade 12. The cutter blade 12 is, for example, a clipper blade. The tread-side arm 13 is capable of moving the cutter blade 12 in the up-down direction and the left-right direction (directions perpendicular to the paper surface of Fig. 1). The left-right direction coincides with the axial direction AD of the tire T (see Fig. 2). Fig. 2 shows an example in which one tread-side removal mechanism 10 is provided. Two tread-side removal mechanisms 10 may be provided along the left-right direction of the trimming device 1.

[0022] During transportation of the tire T, the tread side arm 13 retracts the cutter blade 12 upward so as not to come into contact with the tire T. When removing the spew Sp, the tread side arm 13 moves the cutter blade 12 downward, and moves the cutter blade 12 in the left-right direction (direction perpendicular to the paper surface of FIG. 1) at a predetermined speed while maintaining a predetermined gap between the cutter blade 12 and the tire T.

[0023] As shown in Fig. 1, the sidewall-side removal mechanism 11 includes a cutter blade 12 and a sidewall-side arm 14 that moves the cutter blade 12. The cutter blade 12 provided in the sidewall-side removal mechanism 11 may be the same as or different from the cutter blade 12 provided in the tread-side removal mechanism 10. The sidewall-side arm 14 is capable of moving the cutter blade 12 in the up-down direction and the left-right direction (directions perpendicular to the paper surface of Fig. 1).

[0024] During transportation of the tire T, the sidewall-side arm 14 retracts the cutter blade 12 to the side (in a direction perpendicular to the plane of FIG. 1) so as not to come into contact with the tire T. When removing the spew Sp, the sidewall-side arm 14 moves the cutter blade 12 close to the tire T and moves the cutter blade 12 in the vertical direction at a predetermined speed while maintaining a predetermined gap between the cutter blade 12 and the tire T.

[0025] [Manufacturing method of pneumatic tires] Next, a method for manufacturing a pneumatic tire T will be described with reference to Fig. 1 to Fig. 3. Fig. 3 is a flow chart showing an example of a spew Sp trimming step.

[0026] The manufacturing method of the pneumatic tire T includes a vulcanization process for vulcanizing and molding the tire T, and a trimming process for trimming the spew Sp of the tire T formed in the vulcanization process. The vulcanization process may be the same as a normal method, and can be adopted without any particular restrictions on a conventionally known vulcanizer, mold structure, vulcanization conditions, etc.

[0027] As shown in FIG. 3, the trimming process includes a storage step ST1 in which at least a part of the expandable body 15 shown in FIG. 1 and FIG. 2, which can be expanded by supplying a fluid, is stored inside the tire T, a supporting step ST2 in which the inflated expandable body 15 supports the inner surface Is of the tire T, and a removing step ST3 in which the spew Sp of the tire T supported by the expandable body 15 is removed by the cutter blade 12 shown in FIG. 1. According to this method, the inner surface Is of the tire T is supported by the expandable body 15, so that vertical and horizontal vibrations of the tire T in the removing step ST3 can be suppressed. This stabilizes the gap between the cutter blade 12 and the tire T, and the spew Sp can be accurately removed without assembling the tire T to the rim. In addition, the storage step ST1 and the supporting step ST2 for the expandable body 15 require fewer steps than the steps required for assembling the tire T to the rim, so that an increase in the number of steps due to using the expandable body 15 to remove the spew Sp can be suppressed.

[0028] As shown in Figs. 1 and 2, the expandable body 15 is formed of a material that can be expanded by supplying a fluid. The expandable body 15 is formed of, for example, an elastic material (such as a rubber tube or a rubber bag). The fluid is a gas, a liquid, or a gas-liquid mixture. The fluid is preferably a gas. This makes the expandable body 15 lighter, and suppresses an increase in the load for rotating the tire T supported by the expandable body 15 in the removal step ST3. It is more preferable that the fluid is air.

[0029] The inflatable body 15 has a shape capable of supporting the inner surface Is of the tire T when inflated. The inflatable body 15 has, for example, a circular shape along the circumferential direction CD (see FIG. 1) of the tire T. The inflatable body 15 is preferably an annular tube along the circumferential direction CD of the tire T. This allows the volume of the inflatable body 15 to be smaller than when the inflatable body 15 is disc-shaped, thereby shortening the time required for the inflatable body 15 to expand and contract. For example, an annular tube used in tube tires can be used as the inflatable body 15. Note that the inflatable body 15 is not limited to the above, and may be, for example, a disc-shaped rubber body. In this example, a part (outer periphery) of the inflatable body 15 is accommodated inside the tire T.

[0030] When the expandable body 15 is an annular tube, the inner diameter of the expandable body 15 when supporting the tire T is preferably larger than the minimum diameter D2 in the radial direction RD of the bead portion Bd. This makes it possible to suppress deformation of the tire T (especially the bead portion Bd) due to expansion more than when the expandable body 15 is disk-shaped. As a result, it is possible to suppress the cutter blade 12 from coming into contact with the tire T and damaging its outer surface in the removal step ST3.

[0031] The outer diameter of the inflatable body 15 when not inflated is preferably smaller than the maximum diameter D1 in the radial direction RD (see FIG. 2) of the inner surface Is of the tread Tr. This makes it easier to accommodate the inflatable body 15 inside the tire T in the accommodation step ST1.

[0032] The inflatable body 15 can be used for tires T of multiple sizes. For example, the inflatable body 15 can be used for tires T with rim sizes that differ by 2 or 3 inches. This reduces the number of types of inflatable bodies 15 that need to be prepared according to the size of the tire T.

[0033] The inflatable body 15 is provided with a valve 16 that serves as a fluid supply port. Although an example in which the valve 16 is linear is shown in Figs. 1 and 2, the valve 16 may be L-shaped or the like. The valve 16 is preferably located on the inner side in the axial direction AD of the tire T than the bead portion Bd of the tire T in the removal step ST3. This makes it possible to prevent the cutter blade 12 and the like from coming into contact with the valve 16 in the removal step ST3, and to stabilize the gap between the tire T and the cutter blade 12. As a result, it is possible to suppress the cutter blade 12 from damaging the outer surface of the tire T in the removal step ST3.

[0034] In the accommodation step ST1, at least a portion of the inflatable body 15 is accommodated inside the tire T so that the valve 16 can be visually observed from the outside of the tire T. The accommodation step ST1 may be performed simultaneously with the support step ST2. Specifically, the inflatable body 15 to which a predetermined amount of fluid has been supplied may be accommodated in the tire T. This provides rigidity to the inflatable body 15, making it easier to accommodate the inflatable body 15 inside the tire T.

[0035] In the supporting step ST2, fluid is supplied from the valve 16 to inflate the inflatable body 15 so that the inner surface Is of the tire T is supported by the inflatable body 15. The internal pressure of the tire T supported by the inflatable body 15 may be lower than the normal internal pressure of the tire T mounted on a rim.

[0036] The normal internal pressure is the air pressure set for each tire by each standard in the standard system including the standard on which the tire is based. For truck and bus tires and light truck tires, it is the maximum air pressure for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and "INFLATION PRESSURE" for ETRTO. The normal internal pressure for passenger car tires is usually 180kPa, but for tires labeled "Extra Load" or "Reinforced", it is 220kPa.

[0037] The accommodating step ST1 and the supporting step ST2 are performed prior to the removing step ST3. When the trimming device 1 is used to remove the spew Sp, the accommodating step ST1 and the supporting step ST2 may be performed upstream of the trimming device 1 (the entrance opening and closing mechanism 8) or may be performed inside the trimming device 1 (at the supporting position X1). The accommodating step ST1 and the supporting step ST2 may be performed manually by an operator or by using an apparatus.

[0038] The removal step ST3 is preferably performed using a trimming device 1 having a rotation mechanism 2 that supports and rotates the tire T. According to this method, the spew Sp can be removed efficiently and accurately by using the trimming device 1. If the trimming device 1 that supports the outer surface of the tire T is as shown in Fig. 1, the spew Sp of the tire T supported by the inflatable body 15 can be removed without changing the configuration of the device.

[0039] The manufacturing method of the pneumatic tire T includes a removal step ST4 (see FIG. 3) of removing the inflatable body 15 from the tire T after the removal step ST3. In the removal step ST4, the fluid is removed from the valve 16 to deflate the inflatable body 15, and the inflatable body 15 accommodated inside the tire T is removed. The removal step ST4 is performed, for example, downstream of the trimming device 1 (the discharge path opening and closing mechanism 9). Note that the removal step ST4 may be performed inside the trimming device 1 (at the support position X1).

[0040] [1] As described above, the manufacturing method of the pneumatic tire T disclosed herein includes a trimming process of trimming the spew Sp of the tire T. The trimming process includes a storage process ST1 of storing at least a portion of the expansion body 15, which can be expanded by supplying a fluid, inside the tire T, a supporting process ST2 of supporting the inner surface Is of the tire T with the inflated expansion body 15, and a removing process ST3 of removing the spew Sp of the tire T supported by the expansion body 15 with a cutter blade 12.

[0041] According to this method, vertical and horizontal vibrations of the tire T in the removing step ST3 can be suppressed by supporting the inner surface Is of the tire T with the inflatable body 15. This stabilizes the gap between the cutter blade 12 and the tire T, and allows the spew Sp to be removed with high accuracy.

[0042] [2] Regarding the above-mentioned method [1] for manufacturing the pneumatic tire T, the inflatable body 15 is preferably an annular tube extending along the circumferential direction CD of the tire T.

[0043] According to this method, the volume of the expansion body 15 can be made smaller than when the expansion body 15 is disk-shaped, and the time required for the expansion body 15 to expand and contract can be shortened.

[0044] [3] With regard to the manufacturing method of the pneumatic tire T according to the above [1] or [2], it is preferable that the outer diameter of the inflatable body 15 in an uninflated state is smaller than the maximum diameter D1 of the inner surface Is of the tread Tr of the tire T.

[0045] According to this method, it becomes easy to accommodate the inflatable body 15 inside the tire T in the accommodation step ST1.

[0046] [4] With regard to the above-mentioned methods [1] to [3] for manufacturing a pneumatic tire T, it is preferable that the valve 16 serving as a fluid supply port is located inside the bead portion Bd of the tire T in the axial direction AD of the tire T in the removal step ST3.

[0047] According to this method, it is possible to prevent the cutter blade 12 and the like from coming into contact with the valve 16 in the removal step ST3, and to stabilize the gap between the tire T and the cutter blade 12. This makes it possible to prevent the cutter blade 12 from damaging the outer surface of the tire T in the removal step ST3.

[0048] [5] Regarding the above-mentioned methods [1] to [4] for manufacturing a pneumatic tire T, the removing step ST3 is preferably performed using a trimming device 1 having a rotation mechanism 2 that supports and rotates the tire T.

[0049] According to this method, the trimming device 1 can be used to remove the spew Sp efficiently and accurately.

[0050] The manufacturing method of the pneumatic tire T is not limited to the configuration of the above-mentioned embodiment, and is not limited to the above-mentioned action and effect. In addition, the manufacturing method of the pneumatic tire T can be modified in various ways without departing from the gist of the present invention. For example, it is possible to arbitrarily select one or more of the configurations, methods, etc. according to the various modified examples described below and adopt them in the configurations, methods, etc. according to the above-mentioned embodiment.

[0051] In this embodiment, the removing step ST3 is performed using a trimming device 1, but is not limited to this. For example, the removing step ST3 may be performed manually by an operator. In this example, the tire T is first placed on a rotating table. Then, while rotating the rotating table with one hand, the cutter blade 12 is placed on the outer surface of the tire T with the other hand to remove the spew Sp. [Explanation of symbols]

[0052] 1 ... trimming device, 2 ... rotation mechanism, 3a ... upper roller, 3b, 3c ... lower roller, 4 ... rotation drive member, 5 ... inlet path, 6 ... outlet path, 7 ... outlet member, 8 ... inlet path opening and closing mechanism, 9 ... outlet path opening and closing mechanism, 10 ... tread side removal mechanism, 11 ... sidewall side removal mechanism, 12 ... cutter blade, 13 ... tread side arm, 14 ... sidewall side arm, 15 ... inflatable body, 16 ... valve, 17 ... roller moving mechanism, T ... pneumatic tire, Sp ... spew, Tr ... tread, Sw ... sidewall, Bd ... bead portion, IL ... inner liner, Is ... inner surface, ST1 ... accommodation process, ST2 ... support process, ST3 ... removal process, ST4 ... removal process,

Claims

1. A trimming step of trimming a spew of a pneumatic tire is included, The trimming step includes: a housing step of housing at least a portion of an expansion body that can be inflated by supplying a fluid inside the tire; a supporting step of supporting an inner surface of the tire with the inflated body; and a removing step of removing the spew of the tire supported by the inflatable body with a cutter blade.

2. The method for manufacturing a pneumatic tire according to claim 1 , wherein the inflatable body is an annular tube extending along a circumferential direction of the tire.

3. The method for manufacturing a pneumatic tire according to claim 1 , wherein an outer diameter of the inflatable body when uninflated is smaller than a maximum diameter of an inner surface of a tread of the tire.

4. The method for manufacturing a pneumatic tire according to claim 1 , wherein a valve serving as a supply port of the fluid is located axially inward of a bead portion of the tire in the removing step.

5. The method for manufacturing a pneumatic tire according to claim 1 , wherein the removing step is performed using a trimming device having a rotation mechanism that supports and rotates the tire.

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