Manufacturing method for tire

Abstract

To provide a manufacturing method for a tire capable of accurately reproducing a worn state in a short time.SOLUTION: A manufacturing method for a tire includes: a vulcanization step S1 for forming grooves 3 in a tread part 2 by vulcanization molding; a cutting step S2 for cutting a contact area 2sa using a numerically controlled lathe device 4; a grinding step S3 for grinding the contact area 2sb using a tire grinding device 5; a measurement step S4 for measuring a groove depth d of the groove 3 and a surface roughness r of the contact area 2s; and an inspection step S5 for confirming whether the groove depth d and surface roughness r are within specified ranges. The numerically controlled lathe device 4 includes a cutting blade 4a whose movement is controlled based on pre-stored profile data of the contact area 2sa. In the cutting step S2, the cutting blade 4a is moved by a first movement amount L from one side of the contact area 2sa in a tire axial direction to the other side while rotating the tread part 2. The first movement amount L is greater than an axial width W of the tire in the profile data.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a tire including a tread portion having a worn contact patch. [Background technology]

[0002] Various tire evaluation methods for evaluating the performance of worn tires have been known. For example, Patent Document 1 below describes manufacturing a worn tire by buffing a new tire. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-088309 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the tire manufacturing method of Patent Document 1 requires time to perform buffing to a predetermined amount of wear, and there is also the problem that variations occur during the buffing process.

[0005] The present invention has been devised in view of the above circumstances, and has as its main object to provide a tire manufacturing method that can accurately reproduce the wear state in a short period of time. [Means for solving the problem]

[0006] The present invention is a method for manufacturing a tire including a tread portion having a worn contact surface, comprising: a vulcanization process for forming grooves in the tread portion by vulcanization molding; a cutting process for cutting the contact surface using a numerically controlled lathe; a grinding process for grinding the contact surface using a tire grinding device; a measurement process for measuring the groove depth and the surface roughness of the contact surface; and an inspection process for confirming whether the groove depth and the surface roughness are within specified ranges, wherein the numerically controlled lathe includes a cutting blade whose movement is controlled based on pre-stored profile data of the contact surface, and the cutting process cuts the contact surface by moving the cutting blade from one side of the contact surface in the axial direction of the tire by a first movement amount while rotating the tread portion, and the first movement amount is greater than the axial width of the tire in the profile data. [Effects of the Invention]

[0007] The tire manufacturing method of the present invention, which has the above-mentioned configuration, can accurately reproduce the wear state in a short period of time. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view of a tire manufactured by a tire manufacturing method. [Figure 2] 1 is a flowchart showing one embodiment of a tire manufacturing method of the present invention. [Figure 3] FIG. 1 is a schematic diagram of a numerically controlled lathe device. [Figure 4] FIG. [Figure 5] FIG. 1 is a schematic diagram of a tire grinding device. [Figure 6] FIG. 2 is a schematic diagram of a polishing process. [Figure 7] FIG. 7 is a schematic diagram of FIG. 6 as viewed from direction A. [Figure 8] FIG. 8 is a schematic diagram showing a state in which the belt sander in FIG. 7 has moved. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional schematic diagram of a tire 1 manufactured by the manufacturing method of a tire 1 according to the present embodiment. As shown in FIG. 1, the tire 1 manufactured by the manufacturing method of a tire 1 according to the present embodiment includes a tread portion 2 having a worn contact surface 2s. In FIG. 1, the new contact surface 2sa after vulcanization molding and the contact surface 2sb after a cutting step S2, which will be described later, are indicated by two-dot chain lines. Such a tire 1 is suitable for evaluating performance in a worn state.

[0010] Although a pneumatic tire for a passenger vehicle is shown as an example of the tire 1, the tire is not limited to this form, and various types of tires 1 can be used, such as a heavy-duty tire, a motorcycle tire, a racing tire, an industrial machine tire, an airless tire, etc.

[0011] For example, a plurality of grooves 3 extending in the tire circumferential direction are formed in the tread portion 2. The tread portion 2 is not limited to this embodiment, and for example, a single groove 3 extending in the tire circumferential direction may be formed, or only lateral grooves may be formed. Such a tread portion 2 is useful for understanding performance changes due to the grooves 3 in a worn state.

[0012] Fig. 2 is a flowchart showing a method for manufacturing the tire 1 of this embodiment. As shown in Fig. 1 and Fig. 2, the method for manufacturing the tire 1 of this embodiment includes a vulcanization step S1 for forming grooves 3 in the tread portion 2 by vulcanization molding. Such a vulcanization step S1 can mold a tire 1 in a new, unworn condition.

[0013] Fig. 3 is a schematic diagram of the numerically controlled lathe device 4. As shown in Figs. 1 to 3, the manufacturing method of the tire 1 according to the present embodiment includes a cutting step S2 in which the contact surface 2sa is cut using the numerically controlled lathe device 4. Such cutting step S2 can remove a large amount of the tread portion 2 in a short time, thereby shortening the time required to reproduce the worn state.

[0014] The numerically controlled lathe 4 of this embodiment includes a cutting blade 4a whose movement is controlled based on pre-stored profile data of the contact surface 2sa. Such a numerically controlled lathe 4 is suitable for cutting with high precision and efficiency.

[0015] Fig. 4 is a schematic diagram showing an example of the cutting step S2. As shown in Fig. 3 and Fig. 4, in the cutting step S2 of this embodiment, the cutting blade 4a is moved from one side of the contact patch 2sa in the tire axial direction to the other side by a first movement amount L while rotating the tread portion 2, thereby cutting the contact patch 2sa. This cutting step S2 suppresses variation in the cutting depth of the cutting blade 4a in the tire circumferential direction, allowing for accurate cutting.

[0016] The first movement amount L is desirably larger than the width W in the tire axial direction of the profile data of the tread portion 2. Such cutting step S2 can suppress the occurrence of steps at the cutting start position or cutting end position, and can shorten the time required for the grinding step S3, which will be described later.

[0017] Fig. 5 is a schematic diagram of a tire grinding device 5. As shown in Figs. 1, 2, and 5, the manufacturing method of the tire 1 of this embodiment includes a grinding step S3 of grinding the contact patch 2sb using the tire grinding device 5. Such a grinding step S3 is suitable for finishing the surface roughness of the contact patch 2sb so that it falls within a specified range, and can improve the accuracy of reproducing the wear state.

[0018] 1 and 2, the manufacturing method of tire 1 of this embodiment includes a measurement step S4 of measuring the groove depth d of groove 3 and the surface roughness r of contact patch 2s, and an inspection step S5 of confirming whether groove depth d and surface roughness r are within specified ranges. Such measurement step S4 and inspection step S5 make it possible to confirm that the wear state is accurately reproduced. Therefore, the manufacturing method of tire 1 of this embodiment can accurately reproduce the wear state in a short time.

[0019] In a more preferred embodiment, the measuring step S4 measures the groove depth d and the surface roughness r at a plurality of positions in the tire circumferential direction. For example, the measuring step S4 measures the groove depth d and the surface roughness r at at least four positions in the tire circumferential direction. This measuring step S4 makes it possible to grasp variations in the wear state in the tire circumferential direction.

[0020] In the measurement step S4, it is desirable to measure the groove depth d and the surface roughness r at multiple positions in the tire axial direction. The groove depth d is measured, for example, for each of the multiple grooves 3. The surface roughness r is measured, for example, at least three positions in the tire axial direction. This measurement step S4 makes it possible to grasp the variation in the wear state in the tire axial direction.

[0021] In the inspection step S5, it is desirable to check whether the groove depth d and the surface roughness r at different positions are within specified ranges. For example, the inspection step S5 checks whether the groove depth d and the surface roughness r at different positions are within specified ranges. Such an inspection step S5 can check whether the variations in the tire circumferential direction and the tire axial direction are within specified ranges.

[0022] In the inspection step S5 of this embodiment, it is confirmed whether the average values ​​of the groove depth d and the surface roughness r at different positions in the tire circumferential direction are within a specified range. The specified range of the average value is preferably stricter than the specified range for each of the average values. This inspection step S5 can confirm whether the wear state is accurately reproduced.

[0023] For example, the tire 1 determined to be outside the specified range in the inspection step S5 may be subjected to the polishing step S3 again. In this case, it is preferable to use an abrasive with a smaller particle size in the polishing step S3. Such a polishing step S3 can further reduce the surface roughness r and reduce variations in the tire circumferential direction and tire axial direction.

[0024] 1 to 4, in the cutting step S2, it is desirable to rotate the tread portion 2 by rotating a base 4b to which the tire 1 including the tread portion 2 is fixed. If the tire 1 is a pneumatic tire, the tire 1 is cut, for example, in a state where it is mounted on a regular rim and the internal pressure is adjusted to the regular pressure and no load is applied. Such cutting step S2 allows the tread portion 2 to be rotated stably, which helps to improve the accuracy of the wear state.

[0025] Here, a "genuine rim" is a rim that is determined for each tire by a standard that includes the standards on which pneumatic tires are based, such as a "standard rim" for JATMA, a "design rim" for TRA, or a "measuring rim" for ETRTO. If there is no standard that includes the standards on which pneumatic tires are based, a "genuine rim" is a rim that can be assembled and has the smallest rim diameter and narrowest rim width among rims that do not leak air.

[0026] "Normal internal pressure" is the air pressure set for each tire by a standard system that includes the standards on which pneumatic tires are based. For JATMA, it is the "maximum air pressure." For TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." For ETRTO, it is the "INFLATION PRESSURE." If there is no standard system that includes the standards on which pneumatic tires are based, "normal internal pressure" is the air pressure set for each tire by the manufacturer.

[0027] The profile data based on which the movement of the cutting blade 4a is controlled is, for example, design data. The design data includes, for example, profile data of a new product and profile data of a worn product. Such cutting step S2 can perform high-precision cutting.

[0028] The cutting depth of the cutting blade 4a when moving in the tire axial direction is preferably 0.05 mm or more. When the cutting blade 4a has a cutting depth of 0.05 mm or more, a large amount of the tread portion 2 can be removed in a short time, and the time required to reproduce the worn state can be shortened. From this perspective, the cutting depth of the cutting blade 4a is more preferably 0.10 mm or more, and even more preferably 0.15 mm or more.

[0029] The cutting depth of the cutting blade 4a when moving in the tire axial direction is preferably 0.50 mm or less. By setting the cutting depth of the cutting blade 4a to 0.50 mm or less, variations in the contact patch 2sa can be suppressed and the wear state can be accurately reproduced. From this perspective, the cutting depth of the cutting blade 4a is more preferably 0.45 mm or less, and even more preferably 0.40 mm or less.

[0030] For these reasons, the cutting depth of the cutting blade 4a when moving in the tire axial direction is preferably 0.05 to 0.50 mm, more preferably 0.10 to 0.45 mm, and even more preferably 0.15 to 0.40 mm. The combination of the upper and lower limits of these numerical ranges can be selected arbitrarily.

[0031] FIG. 6 is a schematic diagram showing an example of the grinding step S3, and FIG. 7 is a schematic diagram of FIG. 6 as viewed from direction A. As shown in FIGS. 6 and 7, the tire grinding device 5 of this embodiment includes a belt sander 5a for grinding the ground contact surface 2sb. In the grinding step S3, grinding is preferably performed while replacing the abrasive grain size of the belt sander 5a with a smaller grain size. Such a tire grinding device 5 is suitable for accurately reproducing the wear state and also allows for easy replacement of the abrasive grain.

[0032] In the grinding step S3, for example, the tread portion 2 is rotated at a constant speed while the belt sander 5a is pressed against the tread portion 2 with a constant pressure to grind the contact surface 2sb. Such a grinding step S3 can suppress variations in the tire circumferential direction and accurately reproduce the wear state.

[0033] Fig. 8 is a schematic diagram showing a state in which the belt sander 5a in Fig. 7 has been moved. As shown in Fig. 7 and Fig. 8, in the grinding step S3, it is desirable to move the position where the belt sander 5a is pressed against the tread portion 2 in the tire axial direction. Such a grinding step S3 suppresses axial variation in the tire and can accurately reproduce the wear state.

[0034] In the polishing step S3, the ground contact surface 2s is preferably polished so that the surface roughness r is 20 μm or less. Such a polishing step S3 can accurately reproduce the tread portion 2 in a state close to the actual wear state.

[0035] The amount of polishing in the polishing step S3 is preferably 0.1 mm or more. By having the amount of polishing of 0.1 mm or more, it is possible to eliminate variations due to the cutting step S2 and improve the precision of the wear state. From this viewpoint, the amount of polishing is more preferably 0.2 mm or more, and even more preferably 0.3 mm or more.

[0036] The amount of polishing in the polishing step S3 is preferably 0.9 mm or less. By having the amount of polishing be 0.9 mm or less, the time required for polishing can be shortened, and the worn state can be reproduced in a short time. From this viewpoint, the amount of polishing is more preferably 0.8 mm or less, and even more preferably 0.7 mm or less.

[0037] For these reasons, the polishing amount in the polishing step S3 is preferably 0.1 to 0.9 mm, more preferably 0.2 to 0.8 mm, and even more preferably 0.3 to 0.7 mm. The combination of the upper and lower limits of these numerical ranges can be selected arbitrarily.

[0038] Although a particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment and can be modified and practiced in various ways.

[0039] [Note] The present invention is as follows.

[0040] [Invention 1] A method of manufacturing a tire including a tread portion having a worn contact surface, comprising: a vulcanization step of forming grooves in the tread portion by vulcanization molding; a cutting step of cutting the contact surface using a numerically controlled lathe; a grinding step of grinding the ground contact surface using a tire grinding device; a measuring step of measuring the groove depth of the groove and the surface roughness of the contact surface; an inspection step of confirming whether the groove depth and the surface roughness are within specified ranges; the numerically controlled lathe device includes a cutting blade whose movement is controlled based on pre-stored profile data of the contact surface; the cutting step includes rotating the tread portion while moving the cutting blade from one side of the contact surface in the tire axial direction to the other side by a first movement amount to cut the contact surface; The first movement amount is greater than the tire axial width of the profile data. Tire manufacturing method.

[0041] [Invention 2] The method for producing a tire according to invention 1, wherein the cutting depth of the cutting blade when moving in the axial direction of the tire is 0.05 to 0.50 mm.

[0042] [Invention 3] 3. The method for manufacturing a tire according to claim 1, wherein the cutting step rotates the tread portion by rotating a base to which the tire including the tread portion is fixed.

[0043] [Invention 4] 4. The method for manufacturing a tire according to any one of claims 1 to 3, wherein design data is used as the profile data.

[0044] [Invention 5] The tire grinding device includes a belt sander for grinding the tread surface, 5. A method for manufacturing a tire according to any one of claims 1 to 4, wherein the grinding step grinds the contact surface by rotating the tread portion at a constant speed and pressing the belt sander against the tread portion at a constant pressure.

[0045] [Invention 6] 6. The method for manufacturing a tire according to claim 5, wherein in the grinding step, a position where the belt sander is pressed against the tread portion is moved in the axial direction of the tire.

[0046] [Invention 7] 7. The method for producing a tire according to any one of Inventions 1 to 6, wherein the polishing step polishes the surface so that the surface roughness becomes 20 μm or less.

[0047] [Invention 8] 8. The method for producing a tire according to any one of Inventions 1 to 7, wherein the amount of polishing in the polishing step is 0.1 to 0.9 mm.

[0048] [Invention 9] 9. The method for manufacturing a tire according to any one of Inventions 1 to 8, wherein the measuring step measures the groove depth and the surface roughness at at least four positions in the tire circumferential direction.

[0049] [Invention 10] 10. A tire manufacturing method according to claim 9, wherein the inspection step checks whether the average values ​​of the groove depth and the surface roughness at different positions in the tire circumferential direction are within specified ranges. [Explanation of symbols]

[0050] 1 tire 2 Tread section 2s Wear state of the contact surface 2sa Contact surface before cutting process 2sb Ground surface before polishing process 3 grooves 4. Numerically controlled lathe equipment 4a cutting blade 5 Tire grinding equipment

Claims

1. A method of manufacturing a tire including a tread portion having a worn contact surface, comprising: a vulcanization step of forming grooves in the tread portion by vulcanization molding; a cutting step of cutting the contact surface using a numerically controlled lathe; a grinding step of grinding the ground contact surface using a tire grinding device; a measuring step of measuring the groove depth of the groove and the surface roughness of the contact surface; an inspection step of confirming whether the groove depth and the surface roughness are within specified ranges; the numerically controlled lathe device includes a cutting blade whose movement is controlled based on pre-stored profile data of the contact surface; the cutting step includes rotating the tread portion while moving the cutting blade from one side of the contact surface in the tire axial direction to the other side by a first movement amount to cut the contact surface; the first movement amount is greater than the tire axial width of the profile data; Tire manufacturing method.

2. 2. The tire manufacturing method according to claim 1, wherein the cutting depth of the cutting blade when moving in the tire axial direction is 0.05 to 0.50 mm.

3. The tire manufacturing method according to claim 1 or 2, wherein the cutting step rotates the tread portion by rotating a base to which the tire including the tread portion is fixed.

4. The tire manufacturing method according to claim 1 or 2, wherein design data is used as the profile data.

5. The tire grinding device includes a belt sander for grinding the tread surface, The tire manufacturing method according to claim 1 or 2, wherein the grinding step grinds the contact surface by rotating the tread portion at a constant speed and pressing the belt sander against the tread portion with a constant pressure.

6. The tire manufacturing method according to claim 5 , wherein the grinding step comprises moving a position where the belt sander is pressed against the tread portion in an axial direction of the tire.

7. The tire manufacturing method according to claim 1 or 2, wherein the polishing step polishes the surface so that the surface roughness is 20 μm or less.

8. 3. The tire manufacturing method according to claim 1, wherein the polishing amount in the polishing step is 0.1 to 0.9 mm.

9. The tire manufacturing method according to claim 1 or 2, wherein the measuring step measures the groove depth and the surface roughness at at least four positions in a tire circumferential direction.

10. The tire manufacturing method according to claim 9 , wherein the inspection step checks whether average values ​​of the groove depth and the surface roughness at different positions in the tire circumferential direction are within specified ranges.

Images