Sealant application device and manufacturing method of sealant tire

Abstract

To provide a sealant application device which inhibits influence caused by an inner surface shape of a tire to which a sealant material is applied to achieve high uniformity of a thickness of a sealant layer, and to provide a manufacturing method of a sealant tire.SOLUTION: A sealant application device 70 includes: a nozzle 100 configured to discharge a sealant material 61; a follow-up mechanism 120 having a roller 122 serving as a follow-up part which follows an inner surface shape of a tire 1; and a nozzle fixture 124 serving as a relative position fixing part which fixes a relative position between the nozzle 100 and the roller 122 in a tire radial direction.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a sealant application device and a method for manufacturing a sealant tire.

Background Art

[0002] Conventionally, a pneumatic tire having a puncture prevention function in which a hole in the tire formed at the time of puncture is automatically blocked by a sealant layer provided on the inner surface of the tire is known. For example, Patent Document 1 describes this type of technology.

[0003] Patent Document 1 relates to a method for manufacturing a pneumatic tire having a sealant layer on the inner surface of the tire in the tire radial direction of the inner liner. Patent Document 1 includes a preparation step of preparing a sealant material by mixing raw materials, and a vulcanized tire is rotated around a rotation axis, and the tire is moved in the width direction and the radial direction with respect to a supply port for supplying the sealant material, and the sealant material prepared in the preparation step is applied to the inner surface of the inner liner in the tire radial direction. In the application step, a method for manufacturing a pneumatic tire is described in which the tire is rotated according to a preset rotation speed of the tire for each of a plurality of preset application areas in the width direction of the tire with respect to the inner surface in the tire radial direction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, the inner surface shape of a tire may have height differences such as unevenness (displacement in the tire diameter direction). For example, the inner surface of a tire is not a perfect circle and does not necessarily have a smooth surface. The height difference in the inner surface shape of the tire causes displacement in the distance between the nozzle and the inner surface of the tire, resulting in variations in the thickness of the sealant layer.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide a sealant application device and a method for manufacturing a sealant tire that can achieve high uniformity in the thickness of the sealant layer.

Means for Solving the Problems

[0007] One aspect of the present invention is a sealant application device for forming a sealant layer on the inner surface of a tire, comprising a nozzle for discharging a sealant material, a follow-up mechanism having a follow-up portion that follows the inner surface shape of the tire, and a relative position fixing portion for fixing the relative position in the tire diameter direction between the nozzle and the follow-up portion.

[0008] Another aspect of the present invention is a method for manufacturing a sealant tire for forming a sealant layer on the inner surface of a tire, the method including a step of adjusting the relative position in the tire diameter direction between the nozzle and the follow-up portion, a step of fixing the relative position in the tire diameter direction between the nozzle and the follow-up portion, and a step of discharging a sealant material from the nozzle to form a sealant layer.

Effects of the Invention

[0009] According to the present invention, it is possible to provide a sealant application device and a method for manufacturing a sealant tire that can achieve high uniformity in the thickness of the sealant layer.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

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Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a side view of a tire 1 manufactured by the manufacturing method according to the embodiment. G in FIG. 1 indicates the axis of rotation which is the center of rotation of the tire 1 extending in the front-back direction of the paper of FIG. 1. In FIG. 1, the tire circumferential direction is indicated by an arrow R. FIG. 2 is a diagram schematically showing a cross-section of the tire 1 in the tire rotation axis direction (tire width direction). The tire 1 according to the embodiment is a pneumatic tire that is mounted on a rim (not shown) and filled with internal pressure by air or the like in its inner cavity. The tire 1 according to the embodiment is a tire for a passenger car. Note that the manufacturing method of the tire according to the embodiment is also applicable to the manufacturing methods of tires for various vehicles such as light trucks, trucks, and buses.

[0012] With reference to FIG. 2, the internal structure of the tire 1 will be briefly described. FIG. 2 shows a cross-section of the tire 1 having a symmetric structure in the direction in which the axis of rotation G shown in FIG. 1 extends. The cross-sectional view of FIG. 2 shows the state of the tire 1 in a no-load state in which the tire 1 is mounted on a specified rim (not shown) and filled with a specified internal pressure.

[0013] In FIG. 2, reference symbol S1 is the tire equatorial plane perpendicular to the axis of rotation G. In FIG. 2, the tire rotation axis direction (tire width direction) and the tire diameter direction in this specification are indicated by arrows X and Y, respectively. (The direction of arrow X) is a direction parallel to the axis of rotation G and is the left-right direction of the paper in the cross-sectional view of FIG. 2. The inside in the tire rotation axis direction is the direction approaching the tire equatorial plane S1 and is the center side of the paper in FIG. 2. The outside in the tire rotation axis direction is the direction away from the tire equatorial plane S1 and is the left side and the right side of the paper in FIG. 2. The tire diameter direction (arrow Y direction) is a direction perpendicular to the axis of rotation G and is the up-down direction of the paper in FIG. 2. FIG. 1 shows the tire diameter direction Y. The outside in the tire diameter direction is the direction away from the axis of rotation G and is the upper side of the paper in FIG. 2. The inside in the tire diameter direction is the direction approaching the axis of rotation G and is the lower side of the paper in FIG. 2.

[0014] The tire 1 includes a pair of beads 10 provided on both sides in the tire rotation axis direction, a tread 20 forming a ground contact surface with the road surface, and a pair of sidewalls 30 extending between the pair of beads 10 and the tread 20.

[0015] The pair of beads 10 constitute the inner portion of the tire 1 in the tire diameter direction. To increase the rigidity of this portion, the bead 10 includes rubber with a high modulus. The bead 10 includes an annular bead core 11 in which a plurality of wound metal bead wires are coated with rubber. The bead core 11 serves to fix the tire 1 to the rim.

[0016] The tread 20 includes a belt 21 and a tread rubber 25 disposed outside the belt 21 in the tire diameter direction. The tread rubber 25 has a ground contact surface 25a that contacts the road surface. A plurality of main grooves 26 extending in the circumferential direction are formed in the ground contact surface 25a.

[0017] The belt 21 is a member that reinforces the tread 20. The belt 21 of the embodiment has a two-layer structure including an inner belt 22 and an outer belt 23 disposed outside the inner belt 22 in the tire diameter direction. Both the inner belt 22 and the outer belt 23 have a structure in which a plurality of belt cords such as steel cords are covered with rubber. The inner belt 22 is larger in length in the tire rotation axis direction than the outer belt 23. Therefore, each of both ends 21A of the belt 21 in the tire rotation axis direction is constituted by the end of the inner belt 22 in the tire rotation axis direction. Note that the outer belt 23 may be larger in length in the tire rotation axis direction than the inner belt 22. Further, the belt 21 may have a single-layer structure or a structure of three or more layers.

[0018] The sidewall 30 includes a sidewall rubber 31 that constitutes the outer sidewall surface of the tire 1. The sidewall rubber 31 bends the most when the tire 1 exerts a cushioning action and is usually composed of a flexible rubber having fatigue resistance.

[0019] Although omitted in Fig. 2, carcass plies that form the framework of the tire 1 are embedded inside the tire 1. The carcass plies are embedded inside the tire 1 in such a manner that they pass between a pair of bead cores 11 through a pair of sidewalls 30 and a tread 20. The carcass plies have a structure in which a plurality of ply cords made of insulating organic fiber cords such as polyester or polyamide are coated with rubber, for example. The belt 21 is disposed on the outer side in the tire radial direction of the carcass plies. Although omitted in Fig. 2, an inner liner as a rubber layer that forms the inner wall surface of the tire 1 is provided across between a pair of beads on the inner cavity side of the carcass plies. The inner liner is made of air permeation resistant rubber and prevents the air inside the tire inner cavity from leaking to the outside.

[0020] As shown in Fig. 4, the tire 1 according to the present embodiment further includes a sealant layer 60. The sealant layer 60 is disposed over the entire circumference in the tire circumferential direction in at least a region corresponding to the tread 20 of the tire inner cavity surface formed by the inner liner. The length of the sealant layer 60 in the tire rotation axis direction is larger than the ground contact surface 25a of the tread 20, and both ends 60A of the sealant layer 60 in the tire rotation axis direction are preferably located outside the tire rotation axis direction of both ends of the ground contact surface 25a. Further, the length of the sealant layer 60 in the tire rotation axis direction is smaller than the length of the belt 21 in the tire rotation axis direction, and each of both ends 60A of the sealant layer 60 in the tire rotation axis direction is preferably located inside the tire rotation axis direction of both ends 21A of the belt 21. As will be described later, the sealant layer 60 is formed by winding a strip-shaped sealant material 61 along the tire inner surface in the tire circumferential direction. As the sealant material 61, one having adhesiveness is preferably used, and it is attached to the tire inner cavity surface by the adhesiveness. The thickness of the sealant layer 60 is preferably 2 mm or more.

[0021] FIG. 3 is a developed view showing a part of the circumferential direction of the inner surface of the tire where the sealant material 61 is attached to form the sealant layer 60. In FIG. 3, the tire circumferential direction is indicated by R, and the tire rotation axis direction is indicated by X. As shown in FIG. 3, the sealant layer 60 is formed by one strip-shaped sealant material 61 that is wound along the tire circumferential direction while being attached to the inner surface of the tire. The sealant layer 60 has a plurality of annular winding portions 62 and a plurality of transition portions 63 formed by the sealant material 61.

[0022] The sealant layer 60 is formed by applying the strip-shaped sealant material 61 along the tire circumferential direction while winding it around the entire circumference of the application region of the sealant material 61 in the tire rotation axis direction on the inner surface of the tire, and shifting the winding path one by one in one direction (left direction in FIG. 3) in the tire rotation axis direction. Thereby, the annular winding portions 62 formed by a plurality of sealant materials 61 extending in the tire circumferential direction are arranged in parallel in the tire rotation axis direction. Note that the sealant material 61 may be attached to the inner surface of the tire while shifting in the tire rotation axis direction every one turn, but it may also be attached in two or more layers overlapping at the same position in the tire rotation axis direction.

[0023] In FIG. 3, reference numeral 61A indicates the starting end of the winding of the sealant material 61, and reference numeral 61B indicates the ending end of the winding of the sealant material 61. The sealant material 61 is continuously attached from one end side to the other end side (from the right side to the left side in FIG. 3) of the tire rotation axis direction while winding as shown by the arrow F from the starting end 61A to the ending end 61B.

[0024] The winding portion 62 is formed by attaching the sealant material 61 to the inner surface of the tire in parallel with the tire circumferential direction. The plurality of winding portions 62 are arranged in parallel so as to be adjacent to each other in a closely adjacent state in the tire rotation axis direction. The plurality of transition portions 63 are inclined at a predetermined angle with respect to the tire circumferential direction and are arranged in parallel so as to be adjacent to each other in a closely adjacent state.

[0025] The transition part 63 is provided at a predetermined position in the tire circumferential direction. After the sealant material 61 is affixed almost one full turn to the tire inner surface to form one circumferential part 62, the transition part 63 is the part where the sealant material 61 moves to one side in the tire rotation axis direction (the left side in FIG. 3). After passing through the transition part 63, the next circumferential part 62 is adhesively attached adjacent to one side in the tire rotation axis direction of the already affixed circumferential part 62. The next circumferential part 62 adjacent to one side in the tire rotation axis direction is repeatedly formed after passing through the transition part 63, thereby forming the sealant layer 60. In this way, when affixing the sealant material 61 to the tire inner surface, the method of sequentially arranging the circumferential parts 62 parallel to the tire circumferential direction in the tire rotation axis direction while passing through the transition part 63 is sometimes referred to as step pasting hereinafter.

[0026] As the sealant material 61, for example, an adhesive sealing material in which a plasticizer such as polyisobutylene or polybutene, a tackifier such as a thermoplastic olefin / diolefin copolymer, and a filler such as carbon black or silica are blended in unvulcanized or semi-vulcanized butyl rubber can be used. Note that the sealant material 61 is not limited to this and may be other known sealing materials that have been conventionally used. Also, those having low fluidity and being difficult to flow even during high-speed driving are preferred.

[0027] Next, a sealant coating device 70 for manufacturing the tire 1 having the above configuration will be described. The sealant coating device 70 forms the above sealant layer 60 on the tire obtained by vulcanizing the green tire, which is the prototype of the tire 1 molded to have the above configuration.

[0028] FIG. 4 is a diagram schematically showing a sealant coating device 70 to which the manufacturing method according to the first embodiment is applied. As shown in FIG. 4, the sealant coating device 70 includes a tire holding device 71, a robot 72, a sealant supply device 73, and a following mechanism 120.

[0029] The tire holding device 71 is a tire holding part that holds the tire 1 to which the sealing material 61 is to be applied. The tire holding device 71 of the present embodiment has a gripping part 75 that grips the tire 1. The gripping part 75 is rotationally driven by the tire holding device 71 while gripping the tire 1. As a result, the tire 1 is rotatable in the circumferential direction.

[0030] The tire holding device 71 has an encoder 74 for acquiring the rotation angle of the tire 1 gripped by the gripping part 75. The position in the tire circumferential direction can be acquired based on the rotation angle acquired by the encoder 74.

[0031] An example of the gripping part 75 will be described. Fig. 5 is a schematic view of the gripping part 75 that grips the tire 1 as seen from the side. Fig. 5(a) shows the gripping part 75 before gripping the tire 1, and Fig. 5(b) shows the gripping part 75 after gripping the tire 1. Fig. 6 is a schematic view of the gripping part 75 that grips the tire 1 as seen from the front. Fig. 6(a) shows the gripping part 75 before gripping the tire 1, and Fig. 6(b) shows the gripping part 75 after gripping the tire 1.

[0032] As shown in Figs. 5 and 6, the gripping part 75 includes a base part 76 on which the tire 1 is disposed, and an arm part 77 as a tire gripping part that grips the tire 1 disposed on the base part 76.

[0033] The base portion 76 has a surface that faces the tire 1 in the tire rotation axis direction of the tire 1. The arm portion 77 is configured to be movable in the tire radial direction between an open position located on the outer side in the radial direction and spaced apart from the tire 1 and a gripping position located on the inner side in the radial direction and in contact with the tire 1. When the arm portion 77 moves from the open position to the gripping position with respect to the tire 1 disposed on the base portion 76, the tire 1 is held in a state of being pressed from the outer side to the inner side in the tire radial direction. In the present embodiment, a plurality of arm portions 77 are arranged at equal intervals in the tire circumferential direction, and the tire 1 is gripped so as to be sandwiched between the plurality of arm portions 77. Thereby, when the tire 1 is rotationally driven by the tire holding device 71 and further when the sealant material 61 is applied, it is possible to suppress displacement of the position of the gripped tire 1.

[0034] The robot 72 is a nozzle position control unit that determines the position of the nozzle 100 that discharges the sealant material 61 with respect to the inner surface of the tire 1. The arm 72A (see FIG. 7) of the robot 72 includes a connecting portion 78 to which the follower mechanism 120 is connected. The robot 72 holds the nozzle 100 via the follower mechanism 120. Although the orientation of the nozzle 100 is not limited, in the present embodiment, it is position-controlled to be orthogonal to the inner surface of the tire 1 in the coating process. The robot 72 can hold the nozzle 100 at an appropriate position with respect to the tire 1 according to, for example, the type of the tire 1 and the thickness of the sealant layer 60.

[0035] The sealant supply device 73 supplies the sealant material 61 to the nozzle 100 held by the robot 72. A flow passage 73A (see FIG. 7) for supplying the sealant material 61 from the sealant supply device 73 is connected to the nozzle 100. The flow passage 73A may be configured to be bendable.

[0036] FIG. 7 is a cross-sectional view in the tire rotation axis direction showing the nozzle 100 and the follower mechanism 120 before position adjustment. As shown in FIG. 7, the follower mechanism 120 includes a roller holding portion 121, a roller 122, a variable portion 123, and a nozzle fixture 124.

[0037] The roller holding portion 121 is arranged adjacent to the nozzle 100 in the tire rotation axis direction. The roller holding portion 121 rotatably holds the roller 122 at its tip side and is connected to the variable portion 123 at its base end side.

[0038] The roller 122 is a follower portion that contacts the inner surface of the tire 1 in the coating process. The roller 122 of the present embodiment is a swivel roller that can change its direction by 360 degrees in a plane including the tire circumferential direction and the tire rotation axis direction. The roller 122 may be a ball-type swivel caster in which the rotating part is composed of balls. Note that the rotation direction of the roller as the follower portion is not limited to 360 degrees. A roller that rotates only in the circumferential direction may be used as the follower portion. Thus, the configuration of the follower portion can be changed as appropriate.

[0039] The variable portion 123 is arranged between the connecting portion 78 of the robot 72 and the roller holding portion 121. The connecting portion 78 of the robot 72 and the roller holding portion 121 are connected in the tire radial direction via the variable portion 123. The variable portion 123 is configured to be able to vary the length in the tire radial direction by a spring member 125 having a restoring force that tries to return to its original state, such as a metal spring. The spring member 125 is not limited to a metal spring and may be an air spring or the like. In the present embodiment, a plurality of spring members 125 are arranged at least in the tire rotation axis direction. The spring members 125 may be arranged side by side in the circumferential direction. Note that the number and arrangement location of the spring members 125 of the variable portion 123 are not limited. The operation of the variable portion 123 will be described later.

[0040] The nozzle fixture 124 is a relative position fixing part that fixes the relative position between the roller holding part 121 and the nozzle 100. The nozzle fixture 124 of the present embodiment fixes the position of the nozzle 100 via a nozzle shaft 102 that holds the nozzle 100 located on the tip side. The nozzle shaft 102 is a shaft-like member that moves integrally with the nozzle 100. Note that the nozzle shaft 102 has a configuration having a flow path for transporting the sealant material 61 supplied from the sealant supply device 73 to the nozzle 100, for example. The nozzle shaft 102 functions as a gripping part of the nozzle fixture 124, and the flow path for transporting the sealant material 61 may be provided separately from the nozzle shaft 102.

[0041] The nozzle fixture 124 preferably fixes the nozzle 100 so as to narrow the distance in the tire rotation axis direction between the roller 122 and the nozzle 100 within a range that does not prevent the application of the sealant material 61 by the nozzle 100. The range that does not prevent the application can also be set based on the width in the tire rotation axis direction of the opening 101 of the nozzle 100.

[0042] Also, the nozzle fixture 124 also functions as an adjustment part for adjusting the height (distance in the tire diameter direction) from the inner surface of the tire 1 of the nozzle 100. With reference to FIG. 8, the position adjustment function of the nozzle 100 will be described. FIG. 8 is a cross-sectional view in the tire rotation axis direction showing the nozzle 100 and the follower mechanism 120 after position adjustment.

[0043] The nozzle fixture 124 of the present embodiment has a mechanism capable of changing the position of the nozzle 100 in the tire diameter direction. A hole into which the nozzle shaft 102 can be inserted in the tire diameter direction is formed in the nozzle fixture 124, and the position of the nozzle 100 is fixed by being fastened by a fastening member such as a bolt with the nozzle shaft 102 inserted into the hole of the nozzle fixture 124. The nozzle shaft 102 is slidable in the tire rotation axis direction in a state of being inserted into the nozzle fixture 124, and the position in the tire rotation axis direction can be adjusted. In the example of FIG. 8, the nozzle shaft 102 (nozzle 100) is fixed by the nozzle fixture 124 at a position where the distance from the inner surface of the tire 1 to the nozzle opening 101 of the nozzle 100 is the distance d1.

[0044] The distance d1 is a distance based on the target sealant thickness. The distance based on the target sealant thickness is information that determines the relative positional relationship of the nozzle 100 with respect to the inner surface of the tire 1 set to achieve the target thickness of the sealant layer 60. The distance based on the target sealant thickness may be, for example, the target thickness of the sealant layer 60. Further, the distance based on the target sealant thickness may be set theoretically or empirically based on various factors such as the type of the sealant material 61, the type of the tire 1, and various elements such as the robot 72 in addition to the thickness of the sealant layer 60. Note that the position adjustment function of the nozzle fixture 124 is not limited to this configuration. For example, the adjustment function of the nozzle fixture 124 may be configured by a mechanism that can select a predetermined position from a plurality of preset positions.

[0045] Next, referring to FIG. 9, the inner surface shape of the tire 1 to which the sealant material 61 is applied will be described. FIG. 9 is a graph showing an example of the inner surface shape of the tire 1 in the tire circumferential direction at the center in the tire rotation axis direction. In FIG. 9, the horizontal axis represents the circumferential rotation angle [deg], and the vertical axis represents the radial displacement [mm]. The displacement [mm] may be a measured value or a corrected value obtained by correcting the measured value.

[0046] As shown in FIG. 9, the inner surface of the tire 1 changes in the radial direction according to the change in the rotation angle. For example, since the tire 1 set in the tire holding device 71 is pushed radially inward toward the rotation axis by the arm portion 77 of the gripping portion 75, the displacement of the gripping portion of the arm portion 77 (movement radially inward of the tire) is large. Also, at the joint portion of the inner liner of the tire 1, although not as much as the gripping portion, a relatively large displacement occurs in the same direction (radially inward of the tire) as the gripping portion.

[0047] In this regard, the nozzle 100 of the present embodiment is configured such that its position is displaced according to the inner surface shape of the tire 1 by the roller 122 of the follower mechanism 120. FIG. 10 is a schematic diagram for explaining the positions of the follower mechanism 120 and the nozzle 100 that operate in conjunction with the inner surface shape. In FIG. 10(a), the position of the nozzle 100 for applying the sealing material 61 to a portion where the displacement of the inner surface shape of the tire 1 is 0 or relatively small is shown, and in FIG. 10(b), the position of the nozzle 100 for applying the sealing material 61 to a portion where the displacement of the inner surface shape of the tire 1 is large is shown.

[0048] The portions of the tire 1 shown in FIGS. 10(a) and 10(b) are different portions in the tire circumferential direction or the tire rotation axis direction, but the radial position of the connecting portion 78 of the robot 72 (the control position of the nozzle 100 by the robot 72) is assumed to be the same.

[0049] The length of the variable portion 123 in the radial direction changes according to the amount of movement of the roller holding portion 121. Compared with the state of FIG. 10(a), in the state of FIG. 10(b), the inner surface of the tire 1 is located closer to the inner side in the radial direction, and the amount of movement of the roller 122 and the roller holding portion 121 toward the inner side in the tire radial direction increases.

[0050] Since the control position (position in the tire radial direction) of the robot 72 does not change between the state of Fig. 10(a) and the state of Fig. 10(b), the amount of shrinkage of the variable part 123 is greater in Fig. 10(b) where the movement amount is larger compared to Fig. 10(a). Let the distance between the connecting part 78 and the roller holding part 121 in the state shown in Fig. 10(a), which is the radial length of the variable part 123, be length h1, and let the distance between the connecting part 78 and the roller holding part 121 in the state shown in Fig. 10(b), which is the radial length of the variable part 123, be length h2. Then, the relationship h2 < h1 holds. For example, when the coating position moves from the position in Fig. 10(a) to the position in Fig. 10(b), the radial length of the variable part 123 shrinks from length h1 to length h2 due to the pressing from the inner surface of the tire 1. When the coating position moves from the position in Fig. 10(b) to the position in Fig. 10(a), the radial length of the variable part 123 extends from length h2 to length h1 due to the restoring force of the variable part 123. Thus, even if the inner surface shape of the tire 1 differs in the tire circumferential direction or the tire rotation axis direction, the displacement of the inner surface shape of the tire 1 is absorbed by the variable part 123, so that the radial distance d1 between the nozzle opening 101 of the nozzle 100 and the tire 1 is maintained constant.

[0051] In this embodiment, the sealant material 61 is applied while the nozzle 100 automatically displaces according to the inner surface shape of the tire 1 by the mechanically operating roller 122. Thereby, even on the inner surface where circumferential displacement as shown in Fig. 9 occurs, it is possible to make the thickness of the sealant layer 60 uniform. The configuration of this embodiment is a tire holding device 71 (tire holding part) having a plurality of arm parts 77 (tire gripping parts) that are configured to be movable in the tire radial direction between an open position located on the outer side in the radial direction and separated from the tire 1 and a gripping position located on the inner side in the radial direction and in contact with the tire 1. It is particularly useful in a sealant application device 70 including the tire holding device 71 that gives a plurality of local displacements in the tire radial direction to the inner surface of the tire 1 by the plurality of arm parts 77. Even with such a sealant application device 70, a sealant layer 60 having high uniformity can be formed on the inner surface of the tire 1.

[0052] Next, the process of manufacturing the sealant tire according to the first embodiment will be described. FIG. 11 is a flowchart showing the process flow of the manufacturing process of the sealant tire according to the first embodiment.

[0053] In step S11, a tire holding process is executed in which the tire 1 is held by the gripping portion 75 of the tire holding device 71. In the tire holding process, the tire 1 is attached to the tire holding device 71 in a state where the tire 1 and the nozzle 100 can rotate relative to each other in the tire circumferential direction. In the present embodiment, the tire 1 is placed on the base portion 76 of the gripping portion 75 of the tire holding device 71 and fixed by the arm portion 77, whereby the tire 1 is attached to the tire holding device 71. In the present embodiment, the tire holding device 71 rotates the tire 1, so that the tire 1 rotates relative to the nozzle 100.

[0054] In step S12, a roller contact process is executed in which the robot 72 brings the roller 122 of the follower mechanism 120 into contact with the inner surface of the tire 1. In the roller contact process, the follower mechanism 120 and the nozzle 100 held by the follower mechanism 120 are moved by the robot 72 to the planned coating start position inside the tire 1, and the roller 122 comes into contact with the inner surface of the tire 1 (the state shown in FIG. 7). The movement of the follower mechanism 120 and the nozzle 100 may be performed by an operator.

[0055] In step S13, a setting process is executed in which the setting position in the tire radial direction of the nozzle 100 with respect to the inner surface of the tire 1 is set. The position of the nozzle 100 in the tire radial direction with respect to the inner surface of the tire 1 is set so that the distance to the inner surface of the tire 1 is a distance based on the target sealant thickness. This distance setting may be set, for example, by arranging a laser light reflection type displacement meter on the robot 72 and setting based on the displacement meter, or may be set using an instrument such as a gauge.

[0056] In step S14, a nozzle fixing process is executed in which the position of the nozzle 100 is fixed by the nozzle fixture 124 of the follower mechanism 120, and the nozzle 100 is fixed at the setting position set in step S13 (the state shown in FIG. 8).

[0057] In step S15, an application process is executed in which a sealant material 61 is applied by a nozzle 100 held by a robot 72 via a following mechanism 120 by a tire holding device 71, the robot 72, and a sealant supply device 73.

[0058] As described with reference to FIG. 3, while continuously discharging the sealant material 61 from the nozzle 100 and continuously rotating the tire 1 around the axis, the tire 1 is rotated approximately one turn in a state where the movement in the tire rotation axis direction is stopped, whereby one circumferential portion 62 is applied. Although the control position of the robot 72 is constant, the position of the nozzle 100 moves in the tire diameter direction so that the displacement of the inner surface shape of the tire 1 is absorbed by the following mechanism 120, so that a sealant layer 60 having a uniform thickness is formed on the inner surface of the tire 1. Next, when the nozzle 100 is moved to one side in the tire rotation axis direction by the width of the sealant material 61, a transition portion 63 is applied therebetween. Next, the movement in the tire rotation axis direction is stopped, and a circumferential portion 62 is applied adjacent to the previously applied circumferential portion 62. By repeating the above operations, the sealant material 61 can be applied step by step in the formation region of the sealant layer 60. When the sealant material 61 is applied and affixed to the entire formation region of the sealant layer 60, the discharge of the sealant material 61 from the nozzle 100 is stopped.

[0059] Next, a sealant application device 70 having a configuration different from that of the first embodiment will be described. In the description from the second embodiment onward, components that are common or similar to those of the first embodiment may be denoted by the same reference numerals and detailed description thereof may be omitted.

[0060] Referring to FIG. 12, a following mechanism 120a according to the second embodiment will be described. FIG. 12 is a cross-sectional view in the tire rotation axis direction showing the nozzle 100 and the following mechanism 120a according to the second embodiment. As shown in FIG. 12, the following mechanism 120a of the second embodiment further includes a first load cell 130 and a second load cell 131 as contact detection units in addition to the configuration of the following mechanism 120 of the first embodiment.

[0061] In the second embodiment, the first load cell 130 is disposed on the rotation axis of the roller 122. The first load cell 130 converts the force applied to the rotation axis of the roller 122 into an electrical signal and outputs it to a computer (control device of the sealant application device 70) (not shown). Thereby, it is possible to detect that the roller 122 has come into contact with the inner surface of the tire 1.

[0062] The second load cell 131 is disposed on the lower surface of the connecting portion 78 of the robot 72 to which the upper side of the variable portion 123 is connected. A plurality of second load cells 131 are arranged corresponding to the number of spring members 125 of the variable portion 123. The second load cell 131 converts the force applied to the connecting portion 78 of the robot 72 by the variable portion 123 into an electrical signal and outputs it to a computer (not shown). Note that the second load cell 131 may be disposed on the upper surface of the roller holding portion 121 to which the lower side of the variable portion 123 is connected.

[0063] By disposing the first load cell 130 and the second load cell 131 in the follower mechanism 120a as in the second embodiment, it is possible to detect the reaction force due to the contact between the roller 122 and the inner surface of the tire 1. The detected reaction force can be used for, for example, determining the presence or absence of contact between the inner surface of the tire 1 and the roller 122 and maintaining the contact pressure. For example, in adjusting the position at the start of coating, etc., the contact state of the roller 122 and the deformed state of the variable portion 123 can be monitored to determine whether the contact state is appropriate. Also, in the coating process and the preparation stage before the start of coating, it is also possible to configure to adjust the control position of the robot 72 based on the information detected from the first load cell 130 and the second load cell 131. Note that the arrangement positions and the number of arrangements of the first load cell 130 and the second load cell 131 are not limited to the configuration of the second embodiment and can be changed as appropriate. Also, the load cell may be either the first load cell 130 or the second load cell 131.

[0064] The follower mechanisms 120 of the first embodiment and the follower mechanism 120a of the second embodiment are configured such that the roller 122 is positioned adjacent to the nozzle 100 in the tire rotation axis direction, but the present invention is not limited to this configuration. Next, with reference to FIG. 13, the follower mechanism 120b according to the third embodiment will be described. FIG. 13 is a cross-sectional view in the tire circumferential direction showing the nozzle 100 and the follower mechanism 120b according to the third embodiment.

[0065] As shown in FIG. 13, the roller 122 of the follower mechanism 120b according to the third embodiment is connected to the connecting portion 78 of the robot 72 via the nozzle fixture 124 so as to be positioned adjacent to the nozzle 100 in the tire circumferential direction. In the traveling direction of the nozzle 100 that applies the sealant material 61, the roller 122 is positioned on the front side in the traveling direction of the nozzle 100 so as not to contact the sealant material 61 after application from the nozzle 100. Also with this configuration, the roller 122 follows the displacement of the inner surface of the tire 1 immediately before the application of the nozzle 100, and the distance d1 from the nozzle opening 101 of the nozzle 100 to the inner surface of the tire 1 is maintained.

[0066] FIG. 14 is a cross-sectional view in the tire rotation axis direction showing the nozzle 100 and the follower mechanism 120b according to the third embodiment. In an R portion where the height difference of the inner surface of the tire 1 is large, such as at both ends in the tire rotation axis direction, in a configuration where the roller 122 is positioned adjacent in the rotation axis direction as in the first embodiment or the second embodiment, the inner surface shape of the application position may not be appropriately reflected in the follow-up operation. For example, when the follower mechanisms 120 and 120a of the first embodiment or the second embodiment are used in an R portion as shown in FIG. 14, since the portion where the roller 122 contacts is at a higher position than the portion that is actually applied, there is a possibility that the position of the nozzle 100 will deviate from the distance according to the target sealant thickness due to the operation of the follower mechanisms 120 and 120a. In this regard, according to the configuration of the third embodiment, even in an R portion where the height difference of the inner surface of the tire 1 is large, such as at both ends in the tire rotation axis direction, the roller 122 of the follower mechanism 120b is positioned in the circumferential direction with respect to the nozzle 100 (the position of the dashed line in FIG. 14). Therefore, it is possible to avoid the occurrence of the operation of the follower mechanism 120b that does not reflect the inner surface shape of the application position due to the difference in the position in the tire rotation axis direction.

[0067] According to the above embodiment, the following effects can be obtained.

[0068] (1) The sealant application device 70 according to the embodiment includes a nozzle 100 that discharges a sealant material 61, a following mechanism 120, 120a, 120b having a roller 122 as a following portion that follows the inner surface shape of the tire 1, and a nozzle fixture 124 as a relative position fixing portion that fixes the relative position in the tire diameter direction between the nozzle 100 and the roller 122.

[0069] Thereby, the sealant material 61 is applied while the nozzle 100 is automatically displaced according to the inner surface shape of the tire 1 by the mechanically operating roller 122. Without performing complicated position control by a robot 72 or the like, variations in thickness due to the R portion and unevenness on the inner surface of the tire 1 are suppressed, and a sealant layer 60 having high uniformity can be formed on the inner surface of the tire 1. That is, the relative positional relationship between the inner surface of the tire 1 and the nozzle 100 set initially (the distance between the tip of the nozzle 100 and the inner surface of the tire 1) is constant regardless of the inner surface shape of the tire. Generally, when the sealant layer 60 is disposed on the inner surface of the tire 1, the durability against heat or the like during high-speed running decreases. It is known that this durability affects the thickness of the sealant layer 60, and when the thickness of the sealant layer 60 is increased, the durability decreases. In this regard, with the configuration of the present embodiment, the sealant layer 60 can be accurately and uniformly applied to the application range with a thickness capable of holding air, so that it can be made as thin as possible while ensuring air holding, and both the durability and air holding property of the tire 1 can be realized.

[0070] Generally, in the inner surface shape of a tire, there may be height differences such as unevenness (displacement of the position in the tire diameter direction). For example, the inner surface of the tire is not a perfect circle and does not necessarily have a smooth surface. Also, at both ends in the tire rotation axis direction on the inner surface of the tire, an R portion is formed in the inner surface shape, and there may be unevenness such as bladder marks in the manufacturing process of the tire such as bladder marks. Even for such a tire, with the sealant application device 70 of the present embodiment, a sealant layer 60 having high uniformity can be formed on the inner surface of the tire 1.

[0071] Further, the configuration of the present embodiment is also effective even when the tire is deformed radially inward by the pressing of the device holding the tire in the step of applying the sealant material, and the shape of the inner surface of the tire is deformed. More specifically, the configuration of the present embodiment includes a plurality of arm portions 77 (tire gripping portions) configured to be movable in the tire radial direction between an open position located radially outside and separated from the tire 1 and a gripping position located radially inside and in contact with the tire 1. The tire holding device 71 (tire holding portion) having the plurality of arm portions 77 is also effective in a sealant application device 70 that applies a plurality of local displacements in the tire radial direction to the inner surface of the tire 1 by the plurality of arm portions 77. Even with such a sealant application device 70, a sealant layer 60 having high uniformity can be formed on the inner surface of the tire 1.

[0072] (2) In the embodiment of (1), the tire holding device (tire holding portion) 71 that holds the tire 1 is further provided so that the tire 1 and the nozzle 100 can rotate relative to each other in the circumferential direction of the tire 1.

[0073] Thereby, a sealant application device 70 that can automatically respond to the displacement of the inner surface shape of the tire 1 can be realized by a simple control of maintaining the nozzle 100 at a predetermined control position by a robot 72 or the like while rotating the tire 1 by the tire holding device 71.

[0074] (3) The nozzle fixture 124 according to the embodiment of (1) or (2) is an adjustment portion that adjusts the relative position in the tire radial direction between the nozzle 100 and the roller 122.

[0075] Thereby, since the position of the nozzle 100 that determines the thickness of the sealant layer 60 can be adjusted, an appropriate thickness of the sealant layer 60 corresponding to the type, shape of the tire 1, the holding state of the tire holding device 71, etc. can be realized.

[0076] (4) The nozzle 100 and the roller 122 according to the embodiments of (1) to (3) are arranged so as to be aligned in the tire rotation axis direction.

[0077] As a result, with respect to the unevenness occurring in the tire rotation axis direction due to the gripping portion, the joint portion, the bladder mark, etc., the position of the nozzle 100 can be displaced followingly by the roller 122.

[0078] (5) The nozzle 100 and the roller 122 according to the embodiments (1) to (3) are arranged such that the roller 122 is aligned on the front side in the traveling direction with respect to the nozzle 100 in the tire circumferential direction.

[0079] As a result, in the R portions and the like at both ends of the inner surface of the tire 1 in the tire rotation axis direction where the distance between the nozzle 100 and the inner surface of the tire 1 is greatly or slightly displaced, the occurrence of an operation in which the distance from the nozzle 100 to the inner surface of the tire 1 is not maintained constant can be avoided.

[0080] (6) The roller 122 according to the embodiments (1) to (5) is configured to be rotatable in the tire circumferential direction and is also a roller that can rotate in the tire rotation axis direction.

[0081] As a result, even when a movement including the rotation axis direction from the circumferential portion 62 to the transition portion 63 is performed like step sticking in the coating process, the roller 122 can rotate in the rotation axis direction. Therefore, it is not necessary to raise the position of the nozzle 100 during the movement of the circumferential portion 62 and the transition portion 63, and the coating process can be smoothly performed.

[0082] (7) A method for manufacturing a sealed tire in which a sealant layer is formed on the inner surface of a tire by the sealant coating device according to the embodiment (3) includes a step of adjusting the relative position in the tire diameter direction between the nozzle 100 and the roller 122 as a following portion, a step of fixing the relative position in the tire diameter direction between the nozzle 100 and the roller 122, and a step of discharging the sealant material 61 from the nozzle 100 to form the sealant layer 60.

[0083] Also, according to the method for manufacturing a sealant tire according to the embodiment, the sealant material 61 is applied while the nozzle 100 is automatically displaced according to the inner surface shape of the tire 1 by the mechanically operating roller 122. Without performing complicated control such as that of the robot 72, variations in thickness due to the R portion and unevenness on the inner surface of the tire 1 are suppressed, and a sealant layer 60 having high uniformity can be formed on the inner surface of the tire 1. That is, the relative positional relationship between the inner surface of the tire 1 and the nozzle 100 set initially (the distance between the tip of the nozzle 100 and the inner surface of the tire 1) is constant regardless of the inner surface shape of the tire.

[0084] As described above, the embodiments have been explained. However, the present invention is not limited to the above embodiments, and even if modifications, improvements, etc. are made within the range capable of achieving the object of the present invention, they are included in the scope of the present invention.

[0085] For example, in the above embodiment, an example in which the sealant material 61 is applied by stepwise application has been described. However, the application method of the sealant material 61 is not limited to the configuration of the embodiment. For example, the present invention can also be applied to a configuration in which the sealant material 61 is applied in a spiral shape in the application process. Further, in the above embodiment, the configuration is such that the position of the nozzle 100 is changed while the tire 1 is rotated, but the present invention can also be applied to a configuration in which the nozzle 100 is moved relative to the tire 1.

Explanation of Reference Numerals

[0086] 1 Tire 60 Sealant layer 61 Sealant material 70 Sealant application device 71 Tire holding device (tire holding portion) 72 Robot 73 Sealant supply device 100 Nozzle 120, 120a, 120b Follow-up mechanism 122 Roller (follow-up portion) 124 Nozzle fixture (relative position fixing portion)

Claims

1. A sealant application device for forming a sealant layer on an inner surface of a tire, A nozzle for discharging a sealant material; a following mechanism having a following portion that follows the inner surface shape of the tire; a relative position fixing unit that fixes a relative position between the nozzle and the following unit in a tire radial direction; A sealant application device comprising:

2. a tire holding portion that holds the tire so that the tire and the nozzle are relatively rotatable in a circumferential direction of the tire, The sealant applicator of claim 1 .

3. An adjustment unit that adjusts the relative position of the nozzle and the following portion in the tire radial direction is further provided. The sealant applicator according to claim 1 or 2.

4. The nozzle and the following portion are arranged to be aligned in the tire rotation axis direction. The sealant applicator according to claim 1 or 2.

5. The nozzle and the following portion are arranged in the tire circumferential direction such that the following portion is aligned ahead of the nozzle in the traveling direction. The sealant applicator according to claim 1 or 2.

6. The following portion is a roller configured to be rotatable in the tire circumferential direction and also rotatable in the tire rotation axis direction. The sealant applicator according to claim 1 or 2.

7. A method for manufacturing a sealant tire, comprising forming a sealant layer on an inner surface of a tire by the sealant application device according to claim 3, adjusting a relative position of the nozzle and the following portion in a tire radial direction; Fixing a relative position of the nozzle and the following portion in a tire radial direction; a step of discharging a sealant material from the nozzle to form the sealant layer; A method for producing a sealant tire comprising the steps of:

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