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DE-112018000473-B4 - pneumatic tires

DE112018000473B4DE 112018000473 B4DE112018000473 B4DE 112018000473B4DE-112018000473-B4

Abstract

Pneumatic tires (1), comprising: a pair of bead cores (11), each formed by repeatedly wrapping a tire bead wire (111) in a ring-shaped form, wherein the bead cores (11) each have a wire arrangement structure in the form of a hexagon, which is formed by winding one or more of the tire bead wires (111) in a tightly packed manner in a cross-sectional view of each of the bead cores (11) in its radial direction, where the hexagon is a protruding hexagon with an obtuse interior angle at each vertex, wherein the vertex of the hexagon on a radially innermost side of each of the bead cores (11) is defined as the first vertex P1, wherein a side of the hexagon extending outwards in a tire transverse direction and enclosing the first vertex P1 is defined as a first side S12, wherein an axis parallel to the first side S12 of the hexagon is defined as an X-axis and an axis perpendicular to the X-axis is defined as a Y-axis, where a number of layers M of wire cross-sections in a Y-axis direction and a maximum value N_max of an arrangement number N of wire cross-sections in an X-axis direction have a ratio that satisfies 0.75 ≤ M/N_max ≤ 1.30, and wherein a distance A in the tire transverse direction from the vertex of the hexagon on the innermost side in the tire transverse direction to the center of gravity of the hexagon and a distance B in the tire transverse direction from the vertex of the hexagon on the outermost side in the tire transverse direction to the center of gravity of the hexagon have a ratio that satisfies 1.05 ≤ B/A.

Inventors

  • Koji Nishio

Assignees

  • THE YOKOHAMA RUBBER CO., LTD.

Dates

Publication Date
20260513
Application Date
20180111
Priority Date
20170123

Claims (10)

  1. Pneumatic tire (1) comprising: a pair of bead cores (11) each formed by repeatedly winding a tire bead wire (111) in a ring-shaped form, the bead cores (11) each having a wire arrangement structure in the form of a hexagon formed by winding one or more of the tire bead wires (111) in a tightly packed manner in a cross-sectional view of each of the bead cores (11) are formed in its radial direction, wherein the hexagon is a projecting hexagon with an obtuse interior angle at each vertex, wherein the vertex of the hexagon on a radially innermost side of each of the bead cores (11) is defined as the first vertex P1, wherein a side of the hexagon extending outwards in a tire transverse direction and enclosing the first vertex P1 is defined as a first side S12, wherein an axis parallel to the first side S12 of the hexagon is defined as an X-axis and an axis perpendicular to the X-axis is defined as a Y-axis, wherein a layer number M of wire cross-sections in a Y-axis direction and a maximum value N_max of an arrangement number N of wire cross-sections in an X-axis direction have a ratio that satisfies 0.75 ≤ M/N_max ≤ 1.30, and wherein a distance A in the tire transverse direction from the vertex of the hexagon on the The innermost side in the tire transverse direction to the center of gravity of the hexagon and a distance B in the tire transverse direction from the vertex of the hexagon on the outermost side in the tire transverse direction to the center of gravity of the hexagon have a ratio that satisfies 1.05 ≤ B/A.
  2. pneumatic tires (1) after Claim 1 , wherein the tire bead wire (111) is wound spirally in the X-axis direction to form a layer of wire cross-sections, and a plurality of layers of wire cross-sections are stacked in the Y-axis direction on the first side S12 of the hexagon, which serves as an innermost layer to form the bead core (11).
  3. pneumatic tires (1) according to one of the Claims 1 until 2 , wherein the bead core (11) has the wire arrangement structure in the form of a hexagon formed by winding the single tire bead wire (111) in a tightly packed manner.
  4. pneumatic tires (1) according to one of the Claims 1 until 3 , where the number of arrangements N12 of the wire cross-sections on the first side S12 of the hexagon lies in the following range: 5 ≤ N12.
  5. pneumatic tires (1) according to one of the Claims 1 until 4 , wherein the number of arrangements N23 of the wire cross sections on side S23 in the tire transverse direction outwards, adjacent to the first side S12 of the hexagon, lies in the following range: 2 ≤ N23.
  6. pneumatic tires (1) according to one of the Claims 1 until 5 , wherein the number of wire cross-sections N23 arranged on side S23 in the tire transverse direction outwards, adjacent to the first side S12 of the hexagon, and the number of wire cross-sections N61 arranged on side S61 in the tire transverse direction inwards, adjacent to it, have the ratio 1 ≤ N61 - N23.
  7. pneumatic tires (1) according to one of the Claims 1 until 6 , where the number of arrangements N12 of the wire cross-sections on the first side S12 of the hexagon and the maximum value N_max of the number of arrangements N of the wire cross-sections in the X-axis direction have the ratio 1 ≤ N_max - N12.
  8. pneumatic tires (1) according to one of the Claims 1 until 7 , where the difference in the number of wire cross-sections N in all layers adjacent to each other in the Y-axis direction is -1, 0 or 1.
  9. pneumatic tires (1) according to one of the Claims 1 until 8 , wherein the center of gravity G of the hexagon is positioned inwards in the Y-axis direction of the layer of the tire bead wire (111), which is positioned in the middle in the Y-axis direction of the bead core (11).
  10. pneumatic tires (1) according to one of the Claims 1 until 9 , further comprising: a carcass layer (11) extending between the pair of bead cores (11), wherein both end sections of the carcass layer (11) are bent back outwards in the transverse direction of the tire so that they are wrapped around the corresponding bead cores (11) and are fixed.

Description

Technical field The present invention relates to a pneumatic tire and in particular to a pneumatic tire which can effectively suppress a bead deformation and ensure the core collapse resistance of a bead core in a suitable manner. State of the art Generally, there is a need to suppress bead deformation in heavy-duty tires mounted on trucks or buses. Bead deformation, as described above, is undesirable because it reduces the tire's ease of inflation and also compromises the suitability of the base tire for retreading. The known technology described in the patent documents JP 5071137 B2 , JP H02-37003 A , JP H02-286408 A The tires described are heavy-duty tires that were developed taking this problem into account. US 4 192 368 A reveals a pneumatic tire with asymmetrical bead cores. Brief description of the invention Technical problem To suppress the bead deformation described above, increasing the number of windings of tire bead wires forming a bead core is effective. Unfortunately, increasing the number of windings of tire bead wires causes a problem in that it increases the material costs of the bead cores and circumferential elements (e.g., a rubber material such as bead filler). The present invention is made taking into account the foregoing and one objective thereof is to provide a pneumatic tire which can effectively suppress a bead deformation and ensure the core collapse resistance of a bead core in a suitable manner. Solution to the problem To achieve the above-described objective, a pneumatic tire according to an embodiment of the present invention includes a pair of bead cores, each formed by repeatedly winding a tire bead wire in a ring-shaped form, wherein the bead cores each have a wire arrangement structure in the form of a hexagon formed by winding one or more of the tire bead wires in a tightly packed manner in a cross-sectional view of each of the bead cores in its radial direction, wherein the hexagon is a projecting hexagon with an obtuse internal angle at each vertex, wherein the vertex of the hexagon on a radially innermost side of each of the bead cores is defined as the first vertex P1, wherein a side of the hexagon extending outwards in a tire transverse direction and enclosing the first vertex P1 is defined as a first side S12, wherein an axis parallel to the first side S12 of the hexagon is defined as an X-axis, and an axis perpendicular to the X-axis is defined as a Y-axis is defined, wherein a number of layers M of wire cross-sections in a Y-axis direction and a maximum value N_max of an arrangement number N of wire cross-sections in an X-axis direction have a ratio that satisfies 0.75 ≤ M/N_max ≤ 1.30, and wherein a distance A in the tire transverse direction from the vertex of the hexagon on the innermost side in the tire transverse direction to the centroid of the hexagon and a distance B in the tire transverse direction from the vertex of the hexagon on the outermost side in the tire transverse direction to the centroid of the hexagon have a ratio that satisfies 1.05 ≤ B/A. Advantageous effects of the invention In a pneumatic tire according to one embodiment of the invention, (1) the bead core is formed by winding the tire bead wires in a densely packed manner and has a wire arrangement structure in the form of a protruding hexagon with obtuse internal angles, so that an advantage is that the collapse resistance of the bead core is suitably ensured. In addition, (2) the wire arrangement structure of the bead core is optimized, so that an advantage is that the stroke deformation of the bead core can be effectively suppressed. Brief description of the drawings 1 is a cross-sectional view in a tire meridional direction, showing a pneumatic tire according to an embodiment of the present invention.2 is an enlarged cross-sectional view showing a bead section of the in 1 depicted pneumatic tire.3 is an explanatory diagram that shows a bead core of the in 2 depicted bulge section.4 is an explanatory diagram that shows the bead core of the in 2 depicted bulge section.5 is an explanatory diagram showing a modified example of a wire arrangement structure of the in 3 depicted bulge core.6 is an explanatory diagram that shows a modified example of the wire arrangement structure of the in 3 depicted bulge core.7 is an explanatory diagram that shows a modified example of the wire arrangement structure of the in 3 depicted bulge core.8 is an explanatory diagram that shows a modified example of the wire arrangement structure of the in 3 depicted bulge core.9 is a table showing the results of performance tests of pneumatic tires according to the embodiments of the present invention.10 is an explanatory diagram of the state of the art example 1, which is in 9 is shown.11 is an explanatory diagram of the example of the state of the art 2, which is in 9 is shown.12 is an explanatory diagram of comparison example 1, which is in 9 is shown.13 is an explanatory diagram of comparison example 2, which