Tire molding drum

Abstract

The tire molding drum 4 molds a ring-shaped tire member on the outer peripheral surface of a drum 40. The drum 40 has a first segment 31 on which the front end 22F of a tread member 22 is disposed during winding and a second segment 32 on which the rear end 22R of the tread member 22 is disposed. The first segment 31 and the second segment 32 each have center segments 41, 42 and end segments 51, 52 around which a belt member 24 is wound. The end segments 51 have needle-equipped segments 51A having a plurality of needles 54 inserted into the front end 22F of the tread member 22 and step parts 55 for supporting the tread member 22, and needle-less segments 51B. The end segments 52 and the needle-less segments 51B support a lower surface of the tread member 22.

Description

tire building drum

[0001] The present disclosure relates to tire building drums.

[0002] Japanese Patent Nos. 6,554,467 and 7,291,856 disclose drums for manufacturing tire belts and treads.

[0003] In a conventional truck and bus tire (TBR) building machine, a drum for winding the belt member and tread member is configured with multiple segments arranged circumferentially to enable expansion and contraction to accommodate different tire sizes. The surfaces of these segments have a flat shape in a cross section in the axial direction of the drum. Multiple layers of belt member are wound around the drum, and the tread member is wound around the outer surface of the belt member. In the axial direction of the drum, the width of the tread member is larger than the width of the belt member, and both ends of the tread member in the width direction extend beyond the belt edges, i.e., into areas not supported by the belt members. In particular, since TBR tires have a larger number of belt members than passenger car (PSR) tires, the gap between the tread member extending beyond the belt edges and the drum surface is larger.

[0004] Furthermore, the tread element is made up of a combination of multiple rubber types, and the rubber slabs have complex shapes in different areas. As a result, the contraction conditions of the tread element vary depending on the area and also on the size of the tread element.

[0005] The tread element is cut to a predetermined length and wound around a drum. At this time, the leading and trailing ends of the tread element in the circumferential direction are pressed and joined by a pressure device while overlapping each other on the drum. At this time, due to the existence of a gap between the tread edge and the drum surface and differences in the contraction conditions of each part of the tread element, it was difficult to control the position of the trailing end of the tread edge in the circumferential direction to coincide with the position of the leading end.

[0006] The present disclosure aims to enable a pressure device to automatically join not only the portions of the tread element supported by the belt element but also the tread ends that protrude from the belt element when joining the circumferential leading and trailing ends of the tread element.

[0007] The tire building drum according to the first aspect is a tire building drum for building a ring-shaped tire component by winding tire material around the outer peripheral surface of a substantially cylindrical drum, the drum having a plurality of segments divided in its circumferential direction, the segments having a first segment on which a leading end of a tread component as the tire material is disposed when wound, and a second segment on which a trailing end of the tread component is disposed when wound, the first segment and the second segment being divided into a central segment located on the axial center side of the drum and on which a belt component as the tire material is wound, and a second segment adjacent to the outside of the central segment in the axial direction. The end segments in the first segment each have a needle-attached segment having a plurality of needles that extend from the radially inner side to the radially outer side and are inserted into the tip portion of the tread material when the tread material is wound around the drum, and a needle-less segment that does not have the needles. The end segments in the second segment and the needle-less segment in the first segment are configured to support the underside of the tread material when the tread material is wound around the drum.

[0008] This tire building drum has a first segment on which the leading edge of the tread element is positioned when wound, and a second segment on which the trailing edge of the tread element is positioned when wound. The first segment and the second segment each have a center segment and an end segment. A belt element is wound around the center segment. The tread element is wound onto the belt element. The width of the tread element is greater than the width of the belt element, so that the tread edge extends beyond the belt element.

[0009] The end segments of the first segment include a needle-equipped segment and a needleless segment that does not have needles. When the tread element is wound around the drum, multiple needles extend from the needle-equipped segment from the radially inner side to the radially outer side and are inserted into the tip of the tread edge. This stabilizes the position of the tip of the tread edge of the tread element that protrudes from the belt member.

[0010] Furthermore, when the tread element is wound around the drum, the end segments of the second segments and the needle-less segments of the first segments support the underside of the tread element. This makes it easier to press and extend the rear end of the tread element toward the leading end when the pressure device presses the rear end of the tread element to overlap and bond it to the leading end of the tread element. This allows the rear end of the tread element to be pressed and bonded appropriately to the leading end, enabling the two to be bonded accurately.

[0011] In a second aspect, in the tire building drum according to the first aspect, the positions of the step portions of the needles, the positions of the needle-free segments in the first segment, and the positions of the end segments in the second segment when the tread member is wound around the drum correspond to the positions of the outermost surface of the belt member.

[0012] In this tire building drum, when the tread element is wound around the drum, the positions of the needle step portions, the positions of the needle-free segments in the first segment, and the positions of the end segments in the second segment correspond to the positions of the outermost surface of the belt element. Therefore, the tread edge that protrudes from the belt element when the tread element is wound around the drum can be supported by the needle step portions, the needle-free segments in the first segment, and the end segments in the second segment. This allows the rear end of the tread edge of the tread element to be pressed with a pressure device and joined to the leading end of the tread edge, starting from a position on the second segment farthest from the rear end of the tread edge. This allows the rear end of the tread edge to be pressed and extended even further.

[0013] In a third aspect, in the tire building drum according to the first or second aspect, the position of the tip of the needle in the radial direction of the drum when the needle is extended varies depending on the circumferential position of the drum.

[0014] In this tire building drum, the position of the needle tip in the radial direction of the drum when the needle is extended varies depending on the circumferential position of the drum, so the needle can be inserted along the cross-sectional shape of the leading end of the tread member in the circumferential direction of the drum. This also makes it possible to ensure the needle insertion length while preventing the needle from penetrating the leading end of the tread member. This makes it possible to stabilize the position and shape of the leading end of the tread member.

[0015] In a fourth aspect, in a tire building drum according to any one of the first to third aspects, the end segments are movable in the axial direction of the drum to match the width of the central segment in the axial direction.

[0016] This tire building drum allows the end segments to move axially to match the width of the central segment in the axial direction of the drum, making it possible to accommodate a variety of tire sizes and belt members of various widths.

[0017] According to the present disclosure, when joining the circumferential leading and trailing ends of the tread element, not only the portions of the tread element supported by the belt element but also the tread ends that protrude from the belt element can be automatically joined by a pressure device.

[0018] 7 is a side view showing a schematic configuration of a tire building apparatus; FIG. 8 is a front view showing a pressure device as seen from the X direction of FIG. 1; FIG. 9 is a perspective view showing a portion of a tire building drum according to the present embodiment; FIG. 10 is a front view showing the state of the center segment and the needle-attached segments as seen from the circumferential direction of the drum before the tire material is wound around it; FIG. 11 is a front view showing the state of the center segment and the needle-attached segments as seen from the circumferential direction of the drum when the belt member and the tread member are wound around the drum; FIG. 12 is a side view showing the state of the center segment and the needle-attached segments as seen from the axial direction of the drum before the tire material is wound around it; FIG. 13 is a side view showing the state of the center segment and the needle-attached segments as seen from the axial direction of the drum when the belt member and the tread member are wound around the drum and pressed with a pressure device; FIG. 14 is an enlarged cross-sectional view showing the state of the needle-attached segments in FIG. 15; FIG. 16 is a front view showing the state of the end segment of the second segment as seen from the circumferential direction of the drum before the tire material is wound around it; FIG. 17 is a cross-sectional view showing the state of the end segment of the second segment as seen from the circumferential direction of the drum when the belt member and the tread member are wound around the drum;

[0019] Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. Components indicated by the same reference numerals in each drawing are the same or similar components. Note that duplicated explanations and reference numerals may be omitted in the embodiments described below. Furthermore, all drawings used in the following description are schematic, and the dimensional relationships, ratios, etc. of each element shown in the drawings do not necessarily match those in reality. Furthermore, the dimensional relationships, ratios, etc. of each element between multiple drawings do not necessarily match.

[0020] In the drawings, the direction of arrow C indicates the tire circumferential direction, the direction of arrow R indicates the drum radial direction, and the direction of arrow W indicates the drum width direction. The drum radial direction means a direction perpendicular to the drum rotation axis (not shown).

[0021] 1, the tire building apparatus 1 includes a supply device 3 that supplies tire material 2, a tire building drum 4 on which the tire material 2 is placed, a pressure device 10 for applying pressure to the tire material 2, and a control device (not shown). The tire building apparatus 1 is controlled by the control device to perform a tire building operation, and the pressure device 10 applies pressure to the tire material 2 from the outer periphery.

[0022] The supply device 3 has a conveying device 5 that conveys the tire material 2, and supplies the tire material 2 to the tire building drum 4 in accordance with the rotation of the tire building drum 4. The tire material 2 is wrapped around the outer periphery of the tire building drum 4, placed at a predetermined position on the outer periphery of the tire building drum 4, and molded into a cylindrical shape by the tire building drum 4. During or after the tire material 2 has been placed on the tire building drum 4, a pressure device 10 pressurizes the tire material 2 toward the tire building drum 4.

[0023] 1 and 2 , the pressure device 10 includes a linearly extending shaft member 20, a pair of holding members 11 that hold both ends of the shaft member 20, a plurality of rotatable pressure rolls 12 that surround the shaft member 20, and a moving device 13 that moves the shaft member 20. The shaft member 20 is a non-rotating core member that is disposed inside the plurality of pressure rolls 12 and penetrates the plurality of pressure rolls 12 in the axial direction. The plurality of pressure rolls 12 are aligned in the axial direction of the shaft member 20 and are adjacent to each other in order around the shaft member 20. The pair of holding members 11 connect the shaft member 20 to the moving device 13.

[0024] The moving device 13 is, for example, a piston-cylinder mechanism, and moves the shaft member 20 together with the multiple pressure rolls 12 in the radial direction of the tire building drum 4. The moving device 13 moves the shaft member 20 toward or away from the tire building drum 4. The moving device 13 also moves the multiple pressure rolls 12 between a position in contact with the tire material 2 and a position away from the tire material 2. The multiple pressure rolls 12 are annular pressure members that rotate in contact with the tire material 2, and pressurize the tire material 2 in a predetermined pressure direction P.

[0025] When pressing the tire material 2, the shaft member 20 is disposed along the tire material 2 at the pressing position, and the multiple pressure rolls 12 are arranged in parallel along the outer circumferential surface of the tire material 2. Here, the shaft member 20 is disposed parallel to the axial direction of the tire building drum 4. At predetermined positions in the circumferential direction of the tire building drum 4, the multiple pressure rolls 12 pressurize the entire tire material 2 in the width direction. As the tire building drum 4 rotates, the multiple pressure rolls 12 move relatively in the circumferential direction of the tire building drum 4 to pressurize the entire tire material 2 in the circumferential direction. At this time, the pressing device 10 presses the multiple pressure rolls 12 in the pressing direction P of the tire material 2 using a pressing mechanism (pressure mechanism) (not shown) provided inside the multiple pressure rolls 12. The pressing direction P of the tire material 2 is the direction of pressure applied to the tire material 2 from the pressure rolls 12, and the width direction of the tire material 2 is a direction parallel to the axial direction of the tire building drum 4.

[0026] The multiple pressure rolls 12 operate independently. The pressure device 10 causes the multiple pressure rolls 12 to surround the shaft member 20 and displace each in a predetermined direction around the shaft member 20. Here, the multiple pressure rolls 12 are displaced independently from each other in the pressure direction P of the tire material 2 and the direction opposite to the pressure direction P (for example, the radial direction R). Furthermore, the multiple pressure rolls 12 are each pressed against the tire material 2 to pressurize the tire material 2 in the pressure direction P.

[0027] 3 to 10, tire building drum 4 according to this embodiment is a device that winds tire material 2 around the outer peripheral surface of a substantially cylindrical drum to build a ring-shaped tire component. Tire building drum 4 has a rotating device (not shown) that includes a motor or the like, and drum 40 is rotated at a predetermined speed around its axis by the rotating device.

[0028] The drum 40 has a plurality of segments divided in its circumferential direction. The segments include a first segment 31 on which a leading end 22F (see FIGS. 7 and 8) of a tread element 22 serving as the tire material 2 is disposed when wound, and a second segment 32 on which a trailing end 22R (see FIGS. 7 and 8) of the tread element 22 is disposed when wound. The first segment 31 and the second segment 32 each have a central segment 41, 42 located on the axial center side of the drum 40 and on which a belt element 24 (FIG. 5) serving as the tire material 2 is wound, and end segments 51, 52 adjacent to the outer sides of the central segments 41, 42 in the axial direction. The central segments 41, 42 are replaceable, and the end segments 51, 52 are movable in the axial direction to match the width of the central segments 41, 42 of the drum 40 in the axial direction.

[0029] As shown in Figures 4 to 8, the end segment 51 of the first segment 31 includes a needle-attached segment 51A and a needle-less segment 51B. The needle-attached segment 51A includes a plurality of needles 54 and a step 55 that is integral with the needles 54 and supports the tread element 22 when the needles 54 extend. As an example, the step 55 is the upper end of a large-diameter portion, and the lower end of the large-diameter portion is fixed to a base 58 (described later). The needles 54 have a smaller diameter than the large-diameter portion and are formed with sharp tips. When the tread element 22 is wound around the drum 40, the needles 54 extend from the radially inner side to the radially outer side and pierce the tip end 22F of the tread element 22. A large number of needles 54 are provided in one end segment 51. This is because the needles 54 stabilize the position and shape of the tip end 22F of the tread element 22.

[0030] The needles 54 are erected on, for example, a plate-shaped base 58. The base 58 is supported by a guide 56 that extends in the axial direction of the drum 40. The guide 56 is movable in the radial direction of the drum 40, for example, by extension and contraction of a cylinder device 57. When the guide 56 moves, the base 58 on which the needles 54 are erected also moves in the radial direction of the drum 40.

[0031] The needle segment 51A has a needle cover 60 with a number of through holes 60A corresponding to the needles 54. The needle cover 60 is supported, for example, by a guide 62 extending in the axial direction of the drum 40, and is movable together with the needles 54 and the base 58 when the end segment 52 is moved in the axial direction of the drum 40. The guide 62 is not provided with a cylinder device, and is not movable in the radial direction of the drum 40 except when the entire drum 40 is expanded or contracted. In other words, the needle cover 60 does not move when the needles 54 are advanced or retracted. As a result, the base 58 of the needles 54 moves in the radial direction of the drum 40 due to the expansion and contraction of the cylinder device 57, and the needles 54 advance or retract between a state where they are stored inside the through holes 56A and a state where they protrude outside the through holes 56A.

[0032] 7 and 8 , the position of the tip of the needle 54 in the radial direction of the drum 40 when the needle 54 is extended varies depending on the circumferential position of the drum 40. Specifically, the thickness of the tip portion 22F of the tread member 22 is tapered in circumferential cross section. Corresponding to this shape, the needle 54 that penetrates the portion with a smaller thickness is set to be short, and the needle 54 that penetrates the portion with a larger thickness is set to be long. In other words, the position of the tip of the needle 54 is set so that the tip remains inside the tip portion 22F without penetrating the tip portion 22F.

[0033] The needle-free segment 51B of the end segment 51 does not have needles like the needle-attached segment 51A. This needle-free segment 51B is located adjacent to the needle-attached segment 51A in the circumferential direction of the drum 40, and is located between the end segment 52 of the second segment 32 and the needle-attached segment 51A. The surface of the needle-free segment 51B is formed in a generally arc shape when viewed in the axial direction of the drum 40. In this embodiment, the generally arc shape includes a single arc, a combination of multiple arcs, a combination of an arc and a straight line, etc.

[0034] The needle-free segment 51B is supported by a guide 64 that extends, for example, in the axial direction of the drum 40. The guide 64 is movable in the radial direction of the drum 40 by, for example, the extension and contraction of a cylinder device 66. When the guide 64 moves, the needle-free segment 51B also moves in the radial direction of the drum 40.

[0035] 3, 6, and 9, the end segment 52 of the second segment 32 is supported by, for example, two guides 68. The guides 68 are movable in the radial direction of the drum 40 by, for example, the extension and contraction of a cylinder device 70. When the guides 68 move, the end segment 52 also moves in the radial direction of the drum 40.

[0036] The end segments 52 and the needle-less segments 51B are configured to support the underside of the tread element 22 when the tread element 22 is wound around the drum 40. On the other hand, the central segments 41, 42 are configured not to move in the radial direction of the drum 40 except when the entire drum 40 expands or contracts. Therefore, the end segments 52 of the second segment 32 and the needle-less segments 51B of the first segment 31 can be moved in the radial direction of the drum 40 depending on the thickness of the belt element 24 wound around the central segments 41, 42. This makes it possible for the end segments 52 and the needle-less segments 51B to support the underside of the tread element 22 near the rear end 22R.

[0037] The position of the step 55 when the needle 54 begins to extend is set, for example, to a constant value depending on the thickness of the belt member 24. In other words, the positions of the step 55 of the needle 54 when the tread member 22 is wound around the drum 40, the position of the needle-less segment 51B in the first segment 31, and the position of the end segment 52 in the second segment 32 are configured to correspond to the positions of the outermost surface of the belt member 24.

[0038] (Operation) This embodiment is configured as described above, and its operation will be described below. In Fig. 1, in the tire building apparatus 1, the pressure device 10 pressurizes the tire material 2 placed on the tire building drum 4 with the pressure rolls 12 in a state in which the pressure rolls 12 are displaceable. The pressure device 10 individually controls the pressure of the pressure rolls 12, and pressurizes each portion of the tire material 2 with a predetermined pressure using each pressure roll 12.

[0039] When joining the ends of the tire material 2, for example, the leading end 22F and trailing end 22R of the tread member 22, the tire material 2 is pressed by the multiple pressure rolls 12 while the tire building drum 4 is rotating. At this time, the pressure of each pressure roll 12 is adjusted in accordance with the shape, amount of shrinkage, or amount of elongation of the tire material 2, thereby adjusting the amount of deformation of the tire material 2 by each pressure roll 12. In this way, the ends of the tire material 2 are formed into a target shape and the amount of joining of the tire material 2 is adjusted. In addition, the pressure of the multiple pressure rolls 12 is increased at the joining portion of the tire material 2, thereby reliably joining the tire material 2 at high pressure. When bringing the multiple tire materials 2 arranged on the tire building drum 4 into close contact with each other, the pressure of the multiple pressure rolls 12 is applied to push out air between the multiple tire materials 2, thereby reliably bringing the multiple tire materials 2 into close contact with each other.

[0040] 2, in the tire building drum 4 according to this embodiment, the belt member 24 is wound around the central segments 41, 42. The tread member 22 is wound on the belt member 24. As shown in FIG. 5, the width of the tread member 22 is greater than the width of the belt member 24, and the tread edge protrudes from the belt member 24. In this embodiment, the gap that occurs between the tread edge and the drum 40 can be filled with the needles 54, the step portion 55, the needle-less segment 51B, and the end segment 52.

[0041] The end segments 51 of the first segments 31 include needle-equipped segments 51A and needleless segments 51B that do not have needles. When the tread element 22 is wound around the drum 40, multiple needles 54 extend from the needle-equipped segments 51A from the radially inner side to the radially outer side and are inserted into the tread edge tip portion 22F. This stabilizes the position of the tread edge tip portion 22F of the tread element 22 that protrudes from the belt member 24.

[0042] When the position of the tip of the needle 54 in the radial direction of the drum 40 when the needle 54 is extended varies depending on the circumferential position of the drum 40, the needle 54 can be inserted along the cross-sectional shape of the tip portion 22F of the tread element 22 in the circumferential direction of the drum 40. This makes it possible to ensure the insertion length of the needle 54 while preventing the needle 54 from penetrating the tip portion 22F of the tread element 22. This makes it possible to stabilize the position and shape of the tip portion 22F of the tread element 22.

[0043] 7 and 10 , the positions of the step portions 55 of the needles 54, the positions of the needle-less segments 51B of the first segment 31, and the positions of the end segments 52 of the second segment 32 correspond to the positions of the outermost surface of the belt member 24. In other words, the step portions 55 of the needles 54, the end segments 52 of the second segment 32, and the needle-less segments 51B of the first segment 31 support the underside of the tread element 22.

[0044] Therefore, the tread edge that protrudes from the belt member 24 when the tread element 22 is wound around the drum 40 can be supported by the step portions 55 of the needles 54, the needle-free segments 51B of the first segments 31, and the end segments 52 of the second segments 32. This allows the pressure device 10 to press the rear end portion 22R of the tread edge of the tread element 22 and overlap and bond it to the leading end portion 22F of the tread edge, starting from a position on the second segments 32 far from the rear end portion 22R of the tread edge. This also makes it easier to press and extend the rear end portion 22R of the tread edge toward the leading end portion 22F. Therefore, the rear end portion 22R of the tread edge can be pressed and bonded to the leading end portion 22F appropriately, allowing them to be bonded together with precision.

[0045] The end segments 51, 52 are movable in the axial direction of the drum 40 to match the width of the central segments 41, 42 in the axial direction, and are therefore capable of accommodating belt members 24 of various tire sizes and various widths.

[0046] As described above, according to this embodiment, when joining the leading end 22F and trailing end 22R in the circumferential direction of the tread element 22, the pressure device 10 can automatically join not only the portions of the tread element 22 supported by the belt element 24, but also the tread edges that protrude from the belt element 24. Here, "automatically" means that there is no need for an operator to manually overlap the tread edges.

[0047] [Other Embodiments] Although one example of an embodiment of the present disclosure has been described above, the embodiment of the present disclosure is not limited to the above, and it goes without saying that various modifications can be made without departing from the spirit of the present disclosure.

[0048] The tire building drum 4 may be expandable and contractible as a whole to match the size of the tire components to be manufactured.

[0049] Although the step 55 of the needle 54 corresponds to the position on the outermost surface of the belt member 24 , the step 55 does not necessarily have to correspond to the position on the outermost surface of the belt member 24 .

[0050] Although the end segments 51, 52 are movable in the axial direction of the drum 40 in accordance with the width of the central segments 41, 42 in the axial direction, they are not necessarily movable.

[0051] The disclosure of Japanese Patent Application No. 2023-209487, filed on December 12, 2023, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A tire building drum for building a ring-shaped tire component by winding tire material around the outer circumferential surface of a substantially cylindrical drum, the drum having a plurality of segments divided in the circumferential direction, the segments having a first segment on which a leading end of a tread component as the tire material is disposed when the tread component is wound, and a second segment on which a trailing end of the tread component is disposed when the tread component is wound, the first segment and the second segment each having a central segment located at the axial center of the drum on which a belt component as the tire material is wound, and an end segment adjacent to the outside of the central segment in the axial direction, the end segment of the first segment having a plurality of needles extending from the radial inside to the radial outside when the tread component is wound around the drum and inserted into the leading end of the tread component, and a needleless segment having no needles, a needleless segment in the first segment that is configured to support an underside of the tread element when the tread element is wound around the drum; 2. A tire building drum as described in claim 1, wherein the positions of the step portions of the needles, the positions of the needle-free segments in the first segment, and the positions of the end segments in the second segment when the tread member is wound around the drum correspond to the positions of the outermost surface of the belt member.

3. A tire building drum as set forth in claim 1, wherein the position of the tip of said needle in the radial direction of said drum when said needle is in an extended state varies depending on the circumferential position of said drum.

4. A tire building drum as claimed in claim 1, wherein said end segments are movable axially of said drum to match the width of said central segment in that direction.

Images