JP6153842B2 - Tread tray - Google Patents

Description

  The present invention relates to a tray for tread.

  In general, a tire tread is extruded into a long sheet from an extruder, and is cut into a predetermined length as soon as it is extruded. The tread has a long dimension at high temperature immediately after cutting, but shrinks and shortens as it cools thereafter. At this time, if the tread has a portion that shrinks well and a portion that does not shrink so much, the weight per unit length of the tread becomes uneven.

  When a tire is manufactured by winding such a tread around a belt layer or a belt reinforcing layer in a circumferential shape, the uniformity of the tire is deteriorated. Therefore, it is necessary to eliminate the unevenness of the weight per unit length of the tread.

  Here, as a method for eliminating the unevenness of the weight per unit length of the tread, a method described in Patent Document 1 has been proposed. This is a method of conveying a tread from an extruder to a tire assembling apparatus, in which three divided conveyors are used as a conveyance path, and the speed of each conveyor is devised.

  However, in an actual tire factory, the extruded tread is not immediately transported to the tire assembly apparatus by a conveyor, but is often placed on a flat tray or the like and stored for a long time. Therefore, it is necessary to eliminate not only the weight non-uniformity that occurs during storage, but also during transportation from the extruder to the tire assembly apparatus.

JP-A-4-226332

  As a result of investigation by the inventors of the present application, it has been found that the weight per unit length of the tread after extrusion and cutting increases toward the both ends in the length direction. This is considered because both ends of the tread contract better than the center. Furthermore, immediately after cutting, the weight per unit length near both ends is only 0.8% heavier than that at the center, but it becomes 2.0% heavier if stored on a flat tray for 1 day after cutting. I understood.

  In order to solve this problem, the problem to be solved by the present invention is to provide a tread tray capable of making the weight per unit length of the tread after extrusion uniform.

The tread tray of the embodiment is a tread tray on which a tire tread extruded from an extruder is placed, and the contact area with the lower surface of the tread per unit area of the tread tray is the center in the longitudinal direction of the tread. The portion where the region is placed is characterized by being formed so as to be smaller than the portion where the longitudinal tip region of the tread is placed.

  If the tread tray of the embodiment is used, the weight per unit length of the tread after extrusion can be made uniform.

FIG. 3 is a front view of the tread cart according to the first embodiment. FIG. 3 is a perspective view of the tread tray according to the first embodiment. The elements on larger scale of the AA cross section of the tray for treads of Embodiment 1. FIG. FIG. 6 is a perspective view of a tread tray according to a second embodiment. FIG. 6 is a perspective view of a tread tray according to a third embodiment. FIG. 7 is a perspective view of a tread tray according to a fourth embodiment. Sectional drawing of the state which the tray for treads of Embodiment 4 overlapped.

  The tread tray of the embodiment will be described with reference to the drawings.

(1) Embodiment 1
(1-1) Configuration of Tread Bogie 1 and Tread Tray 10 The tread bogie 1 according to the first embodiment is shown in FIG. 1, and the tread tray 10 is shown in FIGS.

  First, the configuration of the tread cart 1 will be described.

  The tread cart 1 is used for conveying or storing the tread extruded from the extruder to a tire assembling apparatus. The tread bogie 1 includes a rectangular bogie 1a with a wheel at the bottom and columns 1b and 1b erected in the vicinity of two adjacent corners on the upper surface of the bogie 1a. The tread tray 10 is a member having a rectangular shape that is substantially the same size as the chassis 1a in plan view. A part on one side of the tread tray 10 is pivotally supported by a shaft 1c held horizontally between the two pillars 1b and 1b. And the axis | shaft 1c turns into a rotating shaft, and the part by the side of the other side which opposes the said one side of the tray 10 for treads is lifted up or it falls below. And it is held at least in a horizontal state and in a state lifted upward. A large number of tread trays 10 are pivotally supported between the two pillars 1b of the tread cart 1 with a certain distance in the vertical direction.

  On the lower surface side of the portion near the other side of the tread tray 10, a thick plate-like stopper 15 is provided so as to protrude downward. In the state where two or more tread trays 10 are lowered, the stopper 15 of the upper tread tray 10 hits the upper surface of the lower tread tray 10. In this state, the protruding height of the stopper 15 is determined so that the distance between the two tread trays 10 and 10 is kept equal on the one side (shaft support side) and the other side. . Therefore, if the lowermost tread tray 10 is kept horizontal, all the upper tread trays 10 are also kept horizontal.

  Here, a tread placed on the tread tray 10 of the first embodiment will be described.

  The tread has a longitudinal center region and a longitudinal tip region. The central area in the longitudinal direction of the tread is the total length of the tread in the longitudinal direction centered on the center position in the longitudinal direction of the tread (if the end in the longitudinal direction is inclined with respect to the longitudinal direction, The intermediate point of the end point is the apparent end portion, and the length between the apparent end portions on both sides in the longitudinal direction is the total length). The longitudinal tip region is a portion excluding the central region in the longitudinal direction of the tread.

  Next, a detailed configuration of the tread tray 10 will be described.

  The tread tray 10 has a rectangular flat plate 11 having the same size as the upper surface of the chassis 1a in plan view. The flat plate 11 is longer than the length of the tread and has a width that allows two treads to be arranged.

  A large number of free ball bearings 12 are provided as convex portions on a part of the upper surface side of the flat plate 11. The free ball bearings 12 are arranged at regular intervals in the length direction and the width direction of the tread tray 10. The place where the free ball bearing 12 is provided is in a low restraint force region 13 defined below. The range of the low restraining force region 13 in the longitudinal direction of the tread tray 10 is such that the tread is placed on the tread tray 10 and the center position in the longitudinal direction of the tread and the longitudinal center position of the tread tray 10 are matched. Sometimes it is the range in which the central region in the longitudinal direction of the tread rests. The range in the width direction of the tread tray 10 in the low restraining force region 13 is a range from one end to the other end in the width direction of the tread tray 10.

  A portion of the tread tray 10 in the longitudinal direction from the low restraining force region 13 is a flat portion 14.

  The free ball bearing 12 may have a known structure. For example, as shown in FIG. 3, the lower case 12b in which a hemispherical recess 12a is formed, a main ball 12c accommodated in the recess 12a, and the surface of the recess 12a. And a plurality of small balls 12d placed between the main ball 12c, an inner lid 12e and an upper case 12f covering the recess 12a. A window 12g having a diameter smaller than that of the main ball 12c is formed in the upper case 12f, and the upper portion of the main ball 12c is exposed upward from the window 12g. The main ball 12c can be rotated in any direction by an external force.

  The flat plate 11 is formed with a hole into which the lower case 12b of the free ball bearing 12 is inserted. The lower case 12b is inserted into the hole, and the bolt is passed from the upper case 12f to the flat plate 11, whereby the free ball bearing 12 is fixed to the flat plate 11. Thereby, the top of the main ball 12 c of the free ball bearing 12 is exposed above the flat plate 11.

(1-2) Usage of the tread cart 1 and the tread tray 10 The tread is loaded onto the tread cart 1 as follows.

  Initially, all of the tread trays 10 of the tread cart 1 are raised. Next, the lowermost tread tray 10 is lowered onto the chassis 1a and held horizontally. There, the tread extruded from the extruder is placed. At this time, the tread is placed at the center of the tread tray 10 in the longitudinal direction. Two sheets are placed side by side in the width direction. Then, the longitudinal center region of the tread is placed on the free ball bearing 12, and the longitudinal tip region is placed on the flat portion 14. When the tread is placed on the lowermost tread tray 10, the second tread tray 10 on the tread is lowered and held horizontally. In this state, since the stopper 15 of the second tread tray 10 hits the upper surface of the first tread tray 10, the distance between the first and second tread trays 10 and 10 is kept constant. The Therefore, the second tread tray 10 does not hit the tread on the lower first tread tray 10. Thereafter, two treads are placed side by side in the width direction at the center of the second tread tray 10 in the longitudinal direction. The above operation is repeated, and loading of the tread onto the tread cart 1 is completed.

(1-3) Effects When the tread is placed on the tread tray 10 of the first embodiment, the central region in the longitudinal direction of the tread makes point contact with the main ball 12c of the free ball bearing 12 that is a convex portion. Therefore, the central region in the longitudinal direction of the tread is not strongly constrained as compared with the case where the tread is in surface contact with the plane, and contracts better than when placed on the plane.

  On the other hand, the longitudinal tip region of the tread is in surface contact with the flat portion 14. Therefore, it is restrained by the plane part 14 and is hard to shrink | contract.

  As described above, since the central region in the longitudinal direction of the tread that is difficult to contract on the plane contracts well, the amount of contraction is uniform in the central region in the longitudinal direction of the tread and the longitudinal tip region. Therefore, the thickness of the tread and the weight per unit length are uniform. Therefore, tire uniformity (particularly RRO and RFV) using the tread is improved.

  Further, since the main ball 12c of the free ball bearing 12 can freely rotate, the main ball 12c rotates following the displacement in various directions of the point contact portion of the tread accompanying the contraction. Therefore, the central region in the longitudinal direction of the tread that makes point contact with the main ball 12c is not strongly constrained, and contracts better than when it comes into contact with a protrusion that does not rotate freely. As a result, the amount of shrinkage is uniform in the longitudinal center region and the longitudinal tip region of the tread, and the thickness of the tread and the weight per unit length are uniform. Therefore, the uniformity of the tire using this tread is improved.

(1-4) Modified Example In this embodiment, a rotatable member is provided in the low restraint force region 13 of the tray 10 for tread, and the tread portion placed thereon is the tread longitudinal direction, width direction, and It is only necessary to move in an oblique direction with respect to them, and the member is not limited to the free ball bearing 12. For example, a hemispherical recess may be formed directly on the flat plate 11, and a single ball may be rotatably accommodated in the recess with the upper portion exposed.

(2) Embodiment 2
(2-1) Configuration of Tread Tray 20 FIG. 4 shows the tread tray 20 of the second embodiment. The tread tray 20 is used in the same tread cart 1 as in the first embodiment. This tread tray 20 is provided with a roller 22 as a convex portion in a low restraining force region 23. The range of the low restraint force region 23 is the same as the range of the low restraint force region 13 of the first embodiment. The roller 22 has a cylindrical shape that is slightly shorter than the width of the low restraining force region 23, and a rotating shaft projects from both ends thereof. Both sides in the width direction of the low restraining force region 23 are frames 26, and the rotating shaft of the roller 22 is attached to the frame 26 via a bearing so as to be rotatable in two directions. The upper portion of the roller 22 protrudes upward from the height of the flat portion 24 on both sides in the longitudinal direction of the low restraining force region 23. When an external force acts on the protruding portion, the roller 22 rotates in the longitudinal direction of the tread tray 20. A plurality of rollers 22 are provided in the longitudinal direction of the tread tray 20.

(2-2) Effect When the tread is placed on the tread tray 20 of the second embodiment, the central region in the longitudinal direction of the tread is in line contact with the roller 22. For this reason, the central region in the longitudinal direction of the tread is not strongly constrained as compared with the case where the tread is in surface contact with the flat surface, and contracts better than when placed on the flat surface.

  On the other hand, the longitudinal tip region of the tread is in surface contact with the flat surface portion 24. Therefore, it is restrained by the plane part 24 and is hard to shrink | contract.

  As described above, since the central region in the longitudinal direction of the tread that is difficult to contract on the plane contracts well, the amount of contraction is uniform in the central region in the longitudinal direction of the tread and the longitudinal tip region. Therefore, the thickness of the tread and the weight per unit length are uniform. Therefore, the uniformity of the tire using this tread is improved.

  Further, since the roller 22 can freely rotate in the longitudinal direction of the tread, the roller 22 rotates following the displacement in the tread longitudinal direction of the line contact portion of the tread accompanying the contraction. Therefore, the central region in the longitudinal direction of the tread that is in line contact with the roller 22 is not strongly restrained, and contracts well as compared with a case where the tread does not rotate freely. As a result, the amount of shrinkage is uniform in the longitudinal center region and the longitudinal tip region of the tread, and the thickness of the tread and the weight per unit length are uniform. Therefore, the uniformity of the tire using this tread is improved.

(2-3) Modified Example In this embodiment, a member that can rotate in the longitudinal direction of the tread may be provided in the low restraining force region 23 of the tray 20 for tread, and the member is not limited to the roller 22 described above. . For example, a plurality of rollers shorter than the roller 22 are linearly arranged in the width direction of the tread tray 20 to form a roller assembly, and a plurality of roller assemblies are provided in the longitudinal direction of the tread tray 20. May be.

(3) Embodiment 3
(3-1) Configuration of Tread Tray 30 An example of the tread tray of Embodiment 3 is shown in FIG. The tread tray 30 is used in the same tread cart 1 as that of the first embodiment. The tread tray 30 is provided with a convex portion 32 instead of the free ball bearing of the first embodiment and the roller of the second embodiment. The place where the convex portion 32 is provided is the low restraint force region 33. The range of the low restraint force region 33 is the same as the range of the low restraint force region 13 of the first embodiment. Although the shape of the convex part 32 is not limited, in the tray 30 for treads of FIG. 5, it has the shape (sphere crown shape) of the upper part of a sphere. The convex portions 32 are provided side by side in the longitudinal direction and the width direction of the tread tray 30 in the low restraining force region 33.

  Both sides of the tread tray 30 in the longitudinal direction from the low restraining force region 33 are flat portions 34.

(3-2) Effect When the tread is placed on the tread tray 30 of the third embodiment, the central region in the longitudinal direction of the tread comes into contact with the top of the convex portion 32. Therefore, the central region in the longitudinal direction of the tread is not strongly constrained as compared with the case where the tread is in surface contact with the plane, and contracts better than when placed on the plane.

  On the other hand, the longitudinal tip region of the tread is in surface contact with the flat portion 34. Therefore, it is restrained by the plane part 34 and is hard to shrink | contract.

  As described above, since the central region in the longitudinal direction of the tread that is difficult to contract on the plane contracts well, the amount of contraction is uniform in the central region in the longitudinal direction of the tread and the longitudinal tip region. Therefore, the thickness of the tread and the weight per unit length are uniform. Therefore, the uniformity of the tire using this tread is improved.

(3-3) Modified Example The low restraint force region 33 may be provided with a concave portion that is concave with respect to a flat surface having the same height as the flat surface portion 34 instead of the convex portion. Although the shape of a recessed part is not limited, For example, a hemispherical recessed part is mentioned.

  Even when such a recess is provided, the contact area between the tread longitudinal center region and the tread tray 30 is reduced, so that the tread longitudinal center region is not strongly constrained and placed on a flat surface. It shrinks well compared.

  Moreover, the magnitude | size of a convex part and a recessed part is not limited. The convex part and the concave part may be very small, and may be a degree that the surface roughness is recognized as being rough, for example, by measuring the arithmetic average roughness. Even in such a case, since the contact area between the tread longitudinal central region and the tread tray 30 is reduced, the tread longitudinal central region is not strongly constrained and may be compared with a case where the tread is placed on a plane. Shrink.

(4) Embodiment 4
(4-1) Configuration of Tread Tray 40 A tread tray 40 of the fourth embodiment is shown in FIG. The tread tray 40 is used in the same tread cart 1 as that of the first embodiment. The structure of the upper surface of the tread tray 40 of the fourth embodiment may be the same as that of any of the embodiments, but here it is assumed that of the third embodiment. That is, it has the low restraint force area | region 43, and the some convex part 42 is provided there. In addition, both sides of the low restraining force region 43 are flat portions 44.

  A portion of the lower surface of the tread tray 40 on the both ends in the longitudinal direction of the tread tray 40, and when the tread tray 40 overlaps the top and bottom with the sides aligned above the flat portion 44 of the lower tread tray 40 A rectangular parallelepiped abutting member 47 is provided in the portion located at the position.

  A stopper 45 similar to that of the first embodiment is provided on the lower surface of the tread tray 40.

  The thickness of the contact member 47 is such that two tread trays 40 are stacked on the tread carriage 1 and the stopper 45 of the upper tread tray 40 is in contact with the upper surface of the lower tread tray 40. The thickness is such that a gap with a certain width is formed between the lower surface of the contact member 47 of the tread tray 40 and the upper surface of the flat portion 44 of the lower tread tray 40. The constant width is the same width as the thickness of the tread or a width narrower than the thickness of the tread.

  The material of the contact member 47 is not limited, but a material having cushioning properties such as sponge or rubber is desirable. In particular, when the constant width is narrower than the thickness of the tread, it is desirable to have a cushioning property. Here, the cushioning property means that when the abutting member 47 hits the tread, the abutting member 47 has an outer shape of the tread (such as a tip shape of a corner or an uneven shape having a size similar to a groove of a finished tire). (A fine shape is not included) and can be deformed so that a force can be applied from the contact member 47 to the tread in the deformed state.

(4-2) Method of using the tread tray 40 First, the tread T is placed on the lowermost tread tray 40, and then the second tread tray 40 above is lowered and held horizontally. Is done. Then, the front end region in the longitudinal direction of the tread T is sandwiched between the abutting member 47 and the flat portion 44 and is pressed to the flat portion 44 by the abutting member 47. On the other hand, the lower surface of the central region in the longitudinal direction of the tread T is in contact with the top of the convex portion 42, but nothing hits the upper surface. This state is shown in FIG.

  The operation of lowering the tread tray 40 and the operation of placing the tread T on the tread tray 40 are repeated, and the loading of the tread T onto the tread cart 1 is completed.

(4-3) Effects When the tread T is placed on the tread tray 40 of the fourth embodiment, the front end region of the tread T in the longitudinal direction is not only in surface contact with the flat portion 44 but also between the contact member 47 and the flat portion 44. It is sandwiched between and pressed by the flat member 44 by the abutting member 47. Therefore, the front end region in the longitudinal direction of the tread T is restrained, and the contraction is suppressed.

  On the other hand, the central region in the longitudinal direction of the tread T is in contact with the top of the convex portion 42. Also, nothing hits the top surface of the tread T. Therefore, the central region in the longitudinal direction of the tread T is not strongly restrained and contracts well.

  In this way, the longitudinal central region of the tread T, which is difficult to contract on a plane, contracts well, and further the contraction of the longitudinal tip region of the tread T is suppressed, so the amount of contraction is the same as the longitudinal central region of the tread. Uniform with the tip region. Therefore, the thickness of the tread and the weight per unit length are uniform. Therefore, the uniformity of the tire using this tread is improved.

  Further, since the abutting member 47 is attached to the lower surface of the tread tray 40, the tread on the tread tray 40 can be pressed only by overlapping the tread tray 40.

(4-4) Modification Example The contact member may be provided so as to be able to press the longitudinal tip region of the tread T on the tray from above, and is not necessarily attached to the lower surface of the tread tray. good. For example, an openable / closable lid may be provided on the upper surface side of the tread tray, and a contact member may be provided on the lid.

DESCRIPTION OF SYMBOLS 1 ... Tread cart, 1a ... Chassis, 1b ... Column, 1c ... Shaft, 10 ... Tread tray of Embodiment 1, 11 ... Flat plate, 12 ... Free ball bearing, 12a ... Recess, 12b ... Lower case, 12c ... Main Balls, 12d ... small balls, 12e ... inner lid, 12f ... upper case, 12g ... window, 13 ... low restraining force region, 14 ... flat portion, 15 ... stopper, 20 ... tread tray of Embodiment 2, 22 ... roller , 23 ... Low restraint force region, 24 ... Plane portion, 26 ... Frame, 30 ... Tread tray of Embodiment 3, 32 ... Convex portion, 33 ... Low restraint force region, 34 ... Plane portion, 40 ... Embodiment 4 Tread tray, 42 ... convex part, 43 ... low restraint force area, 44 ... flat part, 45 ... stopper, 47 ... contact member, T ... tread

Claims (5)

A tread tray on which a tire tread extruded from an extruder is placed,
The contact area with the lower surface of the tread per unit area of the tray for the tread was formed so that the portion where the central region in the longitudinal direction of the tread is placed is smaller than the portion where the longitudinal tip region of the tread is placed, Tread tray.   2. The tread tray according to claim 1, wherein a convex portion is provided in a portion where the longitudinal center region of the tread is placed, and a portion where the longitudinal tip region of the tread is placed is a flat surface.   The tread tray according to claim 2, wherein the convex portion is a member that can rotate at least in a longitudinal direction of the tread.   The tray for treads of any one of Claims 1-3 provided with the contact member which presses the longitudinal direction front-end | tip area | region of the tread on a tray from upper direction. The abutting member is provided on a lower surface of the tread tray, and in a state where a plurality of the tread trays are stacked, the abutting member of the upper tread tray is a longitudinal tip region of the tread on the lower tread tray. The tread tray according to claim 4, wherein the tread tray is configured to be pressed from above.

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