JP2019051669A - Molding apparatus for tire - Google Patents

Abstract

To provide a molding apparatus enhancing uniformity of a tire.SOLUTION: A molding apparatus 2 includes a pair of set rings 28 for holding a pair of bead members on the outside of a carcass tube in the radial direction. The pair of set rings 28 are formed with a plurality of segment pairs 30 aligned in the circumferential direction. In each of the segment pairs 30, one segment 32 and the other segment 32 are disposed opposing to each other in the axial direction. The molding apparatus includes a function to move each of the segment pairs 30 independently from the other segment pairs 30 in the axial direction, and a function to alter the interval in the axial direction between the one segment 32 and the other segment 32 while holding the central line of the segment pairs 30 in the axial direction to be constant.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pneumatic tire molding apparatus. Specifically, the present invention relates to a molding apparatus including a set ring that holds a bead member.

  The pneumatic tire includes a carcass and a bead. This carcass is formed from a carcass ply. This carcass ply bridges between one bead and the other bead. In a tire, the length of a carcass ply (also referred to as a code path) between a pair of beads is important. If this length is disturbed in the circumferential direction, tire uniformity is impaired.

  In the tire manufacturing method, a cylindrical carcass member is formed by being wound around a drum of a molding apparatus. The bead member is held by the set ring of the molding apparatus and is disposed on the radially outer side of the carcass member. The diameter of the carcass member is expanded, and the bead member is pressure-bonded to the outer peripheral surface of the carcass member. The carcass ply is formed from this carcass member. The bead is formed from this bead member.

  In this manufacturing method, the pair of bead members are pressure-bonded to the carcass member at a predetermined interval. If the gap between the pair of bead members is disturbed in the circumferential direction, tire uniformity is impaired. Japanese Patent Laying-Open No. 2012-139877 discloses a molding apparatus that improves uniformity by eliminating non-uniformity in the tire code path. In this molding apparatus, the uniformity of the set-up is improved by the set ring coming into contact with the bead member while avoiding the protrusion of the rubber of the bead member.

JP 2012-139871 A

  Various factors such as the processing accuracy of the carcass member, the shape of the bead member, and the holding position of the bead member influence the uniformity of the tire. These factors change with long-term use of the molding equipment. Japanese Patent Laid-Open No. 2012-139871 cannot cope with deterioration of uniformity due to these factors.

  It is conceivable to adjust the axial interval of the bead member with respect to the deterioration of uniformity. Thus, it is conceivable to adjust the code path. By adjusting the code path, the radial force variation (hereinafter also referred to as RFV) can be improved. However, the lateral force variation (hereinafter also referred to as LFV) may be deteriorated only by adjusting the code path. Even if the RFV is improved, the uniformity of the tire cannot be improved if the LFV is deteriorated.

  An object of the present invention is to provide a molding apparatus that improves tire uniformity.

The molding apparatus according to the present invention pressure-bonds a pair of bead members with a predetermined cord path to a carcass cylinder in which a carcass member is wound in a cylindrical shape.
The molding apparatus includes a pair of set rings that hold the pair of bead members on the radially outer side of the carcass cylinder.
The pair of set rings are formed of a plurality of segment pairs arranged in the circumferential direction. In each segment pair, one segment and the other segment are arranged to face each other in the axial direction.
In this molding apparatus, each segment pair is axially movable independently from the other segment pairs. The segment pair is configured such that the axial interval between one segment and the other segment can be changed while keeping the axial center line constant.

Preferably, the forming apparatus includes a code path adjusting device. The segment includes a contact portion that contacts the bead member. The circumferential position of one contact portion in the axial direction of the segment pair is the same as the circumferential position of the other contact portion.
The code path adjusting device is
The ability to move each segment pair in the axial direction independently of the other segment pairs;
When one segment of the segment pair is moved in the axial direction, the other segment is provided with a function of moving the other segment in the opposite direction of the movement direction of the one segment by the same movement distance as the one segment.

  Preferably, the molding apparatus includes a position sensor that measures the axial position of each segment.

  Preferably, the movable distance in one axial direction and the movable distance in the other direction of each segment are set to 2 mm or less, respectively.

  Preferably, each contact part is arranged at intervals between other contact parts adjacent in the circumferential direction.

  This molding apparatus includes a control device. Preferably, the control device has a function of storing the RFV data of the tire and a function of calculating the axial interval of the segment for each segment pair from the RFV data.

In the tire manufacturing method according to the present invention, a raw cover including a pair of bead members and a carcass member is vulcanized and a tire is obtained from the raw cover.
The manufacturing method of this tire is:
A cord path adjusting step for adjusting an axial interval between the pair of set rings holding the pair of bead members;
A carcass cylinder preparation step in which a carcass cylinder in which the carcass ply member is wound into a cylindrical shape is prepared;
A pair of bead members, wherein the pair of bead members are held by the pair of set rings, and the pair of bead members are crimped to an outer peripheral surface of the carcass cylinder.
The pair of set rings are formed of a plurality of segment pairs arranged in the circumferential direction. In each segment pair, one segment and the other segment are arranged to face each other in the axial direction.
In the code path adjustment step, each segment pair is moved in the axial direction independently of the other segment pair, and the center line in the axial direction of the segment pair is kept constant, while one segment and the other segment Change the axial spacing.

Preferably, each segment includes a contact portion that contacts the bead member. The circumferential position of one abutting portion in the axial direction is the same as the circumferential position of the other abutting portion.
In the code path adjustment step, one segment of the segment pair moves in the axial direction, and the other segment moves in the opposite direction to the movement direction of the one segment by the same movement distance as the one segment.

  In the molding apparatus according to the present invention, the pair of set rings adjust the cord paths of the pair of bead members. Thereby, RFV can be improved. Furthermore, the axial interval between one segment and the other segment is changed while keeping the axial center line of the segment pair constant. Thereby, the fall of LFV is suppressed. This molding apparatus contributes to improvement of tire uniformity.

FIG. 1 is a conceptual diagram showing a molding apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view showing a pair of set rings of the molding apparatus of FIG. 1. FIG. 3 is an explanatory view showing a use state of the molding apparatus of FIG. 4A is an explanatory view showing another usage state of the molding apparatus of FIG. 1, and FIG. 4B is an explanatory view showing still another usage state of the molding apparatus of FIG. FIG. 4C is an explanatory view showing still another usage state of the molding apparatus of FIG. FIG. 5 is a graph showing the RFV waveform of the tire.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  The molding apparatus 2 in FIG. 1 includes a molding former 4 and a bead transfer 6. Although not shown, the molding apparatus 2 further includes a control device, a position sensor, and a bead supply device.

  The molding former 4 includes a base 10, a support shaft 12, and a drum 14. A support shaft 12 is supported on the base 10 so as to be rotatable about its axis. A drum 14 is attached to the support shaft 12. The drum 14 has a cylindrical shape. The axis of the drum 14 is located on the same straight line as the rotation axis of the support shaft 12. The drum 14 is rotatable together with the support shaft 12.

  The bead transfer 6 includes a guide rail 18, a moving table 20, a ring frame 22, a cord path adjusting device 24, and a pair of set rings 28. The guide rail 18 extends parallel to the axis of the drum 14. The moving table 20 is movable along the guide rail 18. The moving table 20 is movable between a bead supply device (not shown) and the drum 14.

  The ring frame 22 is supported by the movable table 20. The ring frame 22 has a ring shape with a through hole formed in the center. The inner diameter of the through hole is larger than the outer diameter of the drum 14. The axis of the through hole is located on the same straight line as the axis of the drum 14.

  The code path adjusting device 24 includes a plurality of segment adjusting devices 26. Each segment adjusting device 26 is attached to the ring frame 22. The segment adjusting devices 26 are arranged at equal intervals in the circumferential direction of the ring frame 22. In this molding apparatus 2, five segment adjusting devices 26 are arranged at equal intervals. The segment adjusting device 26 includes a main body 26a and a support portion 26b that is movable in the axial direction of the drum 14 with respect to the main body 26a. As the support portion 26b moves relative to the main body 26a, the support portion 26b of the segment adjusting device 26 is movable in the axial direction. The segment moving device 26 includes, for example, a ball screw and a ball screw nut.

  A one-dot chain line Ls in FIG. 2 represents an axis of the pair of set rings 28. The axis Ls is collinear with the axis of the drum 14. The pair of set rings 28 are arranged to face each other in the axial direction. The pair of set rings 28 includes a plurality of segment pairs 30 arranged in the circumferential direction.

  Each segment pair 30 includes one segment 32 in the axial direction and the other segment 32. One segment 32 forms part of one set ring 28. The other segment 32 forms part of the other set ring 28. One segment 32 and the other segment 32 are located at the same position in the circumferential direction of the set ring 28. One segment 32 and the other segment 32 face each other in the axial direction. In the pair of set rings 28, five segment pairs 30 are arranged in the circumferential direction.

  Each segment 32 includes a main body 34 and a contact portion 36. The contact portion 36 is located on the radially inner side of the main body 34. The contact portion 36 is located at the center of the main body 34 in the circumferential direction. The contact portion 36 protrudes inward in the axial direction from the main body 34. An electromagnet is embedded in the contact portion 36. The contact portion 36 includes a contact surface 36. Each contact part 36 is arranged at an interval from another contact part 36 adjacent in the circumferential direction.

  A segment adjusting device 26 is attached to each segment 32 (see FIG. 1). The segment 32 is movable in the axial direction by the segment adjusting device 26. The segment 32 is independent of other segments 32 adjacent in the circumferential direction and is movable in the axial direction.

  Although not shown, the control device includes an input unit that inputs data, a storage unit that stores data, an arithmetic unit that performs calculation, and an output unit that outputs data. This control device has a function of receiving position data from the position sensor and a function of controlling the segment adjustment device 26.

  The position sensor has a function of measuring the axial position of the segment 32. In the molding apparatus 2, the position sensor has a function of measuring the position of the contact surface 36 a of the contact part 36. As this position sensor, for example, a laser sensor is used. In the molding apparatus 2, the segment 32 has a reference position in the axial direction. The position sensor can measure the axial distance from the position of the contact surface 36a at the reference position to the position of the contact surface 36a to be measured.

  FIG. 3 shows a pair of set rings 28, a bead member B, and a carcass cylinder C together with the drum 14. In FIG. 3, the left-right direction is the axial direction of the drum 14, the up-down direction is the radial direction of the drum 14, and the direction perpendicular to the paper surface is the circumferential direction of the drum 14. An alternate long and short dash line Lc represents a center line that is equidistant from the pair of set rings 28 in the axial direction.

  The drum 14 includes a large number of drum segments 16 divided in the circumferential direction. Each drum segment 16 forms part of the outer peripheral surface of the drum 14. The drum segments 16 are arranged in the circumferential direction to form a cylindrical drum 14. The drum segment 16 is movable in the radial direction. The drum segment 16 moves in the radial direction, so that the drum 14 can be expanded and contracted.

  The bead member B includes a core member Bc and an apex member Ba extending radially outward from the core member Bc. The core member Bc is ring-shaped and includes a wound non-stretchable wire of magnetic material. A typical material for the wire is steel. The apex member Ba has a shape that tapers outward in the radial direction. The carcass member of the carcass cylinder C includes a large number of cords arranged in parallel and a topping rubber. The cord is made of organic fiber. Examples of preferable organic fibers include polyester fibers, nylon fibers, rayon fibers, polyethylene naphthalate fibers, and aramid fibers.

  FIG. 4A shows a state in which the segment 32 holds the bead member B. The bead member B is adsorbed to the contact portion 36 of the segment 32 by an electromagnet. The contact surface 36a is in contact with the core member Bc. The segment 32 is at the axial reference position.

  A dashed line in FIG. 4B represents the segment 32 at the axial reference position. In FIG. 4B, one segment 32 of the segment pair 30 is positioned inward by a distance D1 in the axial direction, and the other segment 32 is positioned inward by a distance D1 in the axial direction.

  An alternate long and short dash line in FIG. 4C represents the segment 32 at the axial reference position. In FIG. 4C, one segment 32 of the segment pair 30 is positioned outward by a distance D2 in the axial direction, and the other segment 32 is positioned outward by a distance D2 in the axial direction.

  FIG. 5 shows an RFV of a tire manufactured using the molding apparatus 2. In this tire, RFV is large at a position of 0 ° in the circumferential direction, and RFV is small at a position of 180 °. This tire has a large radius at 0 ° in the circumferential direction and a small radius at 180 °. In this tire, the code path at 0 ° in the circumferential direction is large, and the code path at 180 ° is small.

  Hereinafter, the molding method of a raw cover is demonstrated using this shaping | molding apparatus 2. FIG. This raw cover molding method includes a cord path adjustment step, a carcass cylinder preparation step, and a beat member crimping step.

  In the code path adjustment process, the RFV data of the tire manufactured using the molding device 2 is input to the control device. For example, the RFV data shown in FIG. 5 is input to the control device. The control device stores this RFV data. The controller calculates the axial spacing of each segment pair 30 from the RFV data. The control device transmits the axial interval data of each segment pair 30 to the code path adjusting device 24.

  The code path adjusting device 24 receives the axial interval data of each segment pair 30. The code path adjusting device 24 changes the axial interval of the segment pair 30 by each segment adjusting device 26 based on the axial interval data. For example, in the segment pair 30 at the position of 0 °, as shown in FIG. 4B, each segment 32 is moved inward in the axial direction by the same distance D1. In the segment pair 30 at the position of 180 °, as shown in FIG. 4C, each segment 32 is moved outward in the axial direction by the same distance D2.

  In the carcass cylinder preparation step, a sheet-like carcass ply is prepared. The drum 14 of the molding apparatus 2 rotates. A carcass ply is wound around the outer periphery of the rotating drum 14. The carcass ply is wound in a cylindrical shape to form the carcass cylinder C.

  In the beat member crimping process, the bead supply device supplies the pair of bead members B to the pair of set rings 28. The bead B is adsorbed to the contact portion 36 of the segment 32. The bead transfer 6 moves toward the set position of the bead member B in FIG. The bead transfer 6 stops at this set position. The drum segment 16 of the drum 14 is expanded in diameter, and the bottom surface of the bead member B is pressed against the carcass cylinder C. In this way, the pair of bead members B are attached to the carcass cylinder C. A pair of set rings 28 separate from the drum 14.

  After this bead member crimping step, the end of the carcass cylinder C is folded back. A member forming a sidewall or the like is attached. The carcass cylinder C is shaped into a toroid by a shaping former (not shown), and members for forming a tread, a belt and the like are attached. In this way, the raw cover is formed.

  The manufacturing method of the tire using this shaping | molding apparatus 2 is equipped with the preforming process and the vulcanization process. The pre-forming step is the same as the above-described raw cover forming method, and the description thereof is omitted. In the vulcanization process, the raw cover is put into a mold and pressurized and heated. Thereby, a pneumatic tire is obtained from the raw cover.

  In the molding apparatus 2, the code path adjusting device 24 moves each segment pair 30 in the axial direction independently of the other segment pairs 30. Further, when one segment 32 of the segment pair 30 is moved in the axial direction, the other segment 32 is moved in the direction opposite to the movement direction of the one segment 32 by the same movement distance as the one segment 32. In this molding apparatus 2, even if the code path is adjusted, the center line of the segment pair 30 is kept constant. Thereby, deterioration of LFV and CON is suppressed. The molding apparatus 2 can improve RFV while suppressing deterioration of LFV and CON.

  The molding apparatus 2 includes a position sensor that measures the axial position of each segment 32. The molding apparatus 2 can accurately measure the axial position of the segment 32. The molding apparatus 2 can adjust the axial position of the segment 32 with high accuracy.

  In the molding apparatus 2, the axial interval of the segments 32 corresponding to the axial direction is changed while keeping the position of the axial center line of the pair of segments 30 constant. By moving each segment pair 30 in the axial direction independently of the other segment pairs 30 adjacent in the circumferential direction, the code path can be easily adjusted over the entire circumference. If the deviation of the axial position of the segments 32 adjacent in the circumferential direction becomes too large, the uniformity is deteriorated. From this viewpoint, the one-way movable distance and the other-direction movable distance of the segment 32 are preferably 2 mm or less, respectively.

  In the molding apparatus 2, each segment pair 30 is moved in the axial direction independently of the other segment pair 30. In the circumferential direction, each contact portion 36 is spaced from another adjacent contact portion 36. Even when the axial positions of other adjacent contact portions 36 are shifted due to this interval, each contact portion 36 can securely adsorb the bead member B. From this viewpoint, preferably, the circumferential length of the contact portion 36 is smaller than the circumferential length of the interval between the adjacent contact portions 36, and more preferably, the circumferential length of the contact portion 36 is It is 1/2 or less of the circumferential length of the interval.

  In this molding apparatus 2, the control device calculates the axial interval of the segments 32 for each segment pair 30 from the RFV data. The code path adjusting device 24 moves the segment pair 30 to a position based on the axial interval data. Thereby, as for this shaping | molding apparatus 2, the deterioration of RFV is suppressed. From this point of view, it is preferable that the molding apparatus 2 regularly adjusts the axial interval of the segments 32 for each segment pair 30 based on the RFV data. The axial interval of the segments 32 may be adjusted every time, every fixed quantity, or at a fixed time interval.

  This disorder of the code path is caused by a combination of various factors such as the machining accuracy of the carcass member C, the shape of the bead member B, and the holding position of the bead member B. In the molding apparatus 2, it is not easy to identify the cause and take countermeasures. In this forming apparatus 2, the disorder of the code path can be easily suppressed by adjusting the position of the segment pair 30. The molding apparatus 2 can easily produce a tire having excellent uniformity without impairing productivity.

  Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be construed in a limited manner based on the description of the examples.

[Example]
Tires were produced using the molding apparatus according to the present invention. The tire size was 235 / 45R19. 50 tires were prototyped.

[Comparative example]
Tires were produced using conventional molding equipment. Other than that, 50 tires were prototyped in the same manner as the example.

[Uniformity evaluation]
In accordance with the uniformity test method specified in “JASO C607: 2000”, radial force variation (RFVOA, RFV1H), lateral force variation (LFVOA), and conicity (CON) are applied under the following conditions. It was measured. RFVOA represents the measurement result of the overall RFV, RFV1H represents the measurement result of the primary component, and LFVOA represents the measurement result of the overall LFV. The average value and the standard deviation σ of the results of measuring 50 tires are shown in Table 1 below. The smaller these numbers, the higher the evaluation.
Internal pressure: 200 kPa
Load: 5kN
Speed: 30km / h

  As shown in Table 1, the tire of the example has a higher evaluation than the tire of the comparative example. From this evaluation result, the superiority of the present invention is clear.

  The molding apparatus described above can be widely applied to the manufacture of pneumatic tires.

DESCRIPTION OF SYMBOLS 2 ... Molding device 4 ... Molding former 6 ... Bead transfer 14 ... Drum 16 ... Segment 24 ... Code path adjusting device 26 ... Segment adjusting device 28 ... Set ring 30 ... Segment pair 32 ... Segment 36 ... Contact part

Claims (8)

A molding apparatus that crimps a pair of bead members to a carcass cylinder wound with a carcass member in a predetermined cord path,
A pair of set rings that hold the pair of bead members radially outward of the carcass cylinder,
The pair of set rings are formed of a plurality of segment pairs arranged in the circumferential direction,
In each segment pair, one segment and the other segment are arranged to face each other in the axial direction,
Each segment pair is axially movable independently of the other segment pair,
A molding apparatus in which the segment pair is capable of changing an axial interval between one segment and the other segment while keeping the axial center line constant. It has a code path adjustment device,
The segment includes a contact portion that contacts the bead member, and the circumferential position of one contact portion in the axial direction of the segment pair and the circumferential position of the other contact portion are the same.
The code path adjusting device is
The ability to move each segment pair in the axial direction independently of the other segment pairs;
2. The molding according to claim 1, wherein when one segment of the segment pair is moved in the axial direction, the other segment is moved in the direction opposite to the movement direction of the one segment by the same movement distance as the one segment. apparatus.   The molding apparatus according to claim 1, further comprising a position sensor that measures an axial position of each segment.   The molding apparatus according to any one of claims 1 to 3, wherein a movable distance in one axial direction and a movable distance in the other direction of each segment are set to 2 mm or less, respectively.   5. The molding apparatus according to claim 1, wherein each of the contact portions is arranged with a space between the contact portions adjacent to each other in the circumferential direction. Equipped with a control device,
The molding according to any one of claims 1 to 5, wherein the control device has a function of storing tire RFV data and a function of calculating an axial interval of segments for each segment pair from the RFV data. apparatus. A tire manufacturing method in which a raw cover including a pair of bead members and a carcass member is vulcanized to obtain a tire from the raw cover,
A cord path adjusting step for adjusting an axial interval between the pair of set rings holding the pair of bead members;
A carcass cylinder preparation step in which a carcass cylinder in which the carcass ply member is wound into a cylindrical shape is prepared;
A pair of bead members, wherein the pair of bead members are held by the pair of set rings, and the pair of bead members are crimped to the outer peripheral surface of the carcass cylinder,
The pair of set rings are formed of a plurality of segment pairs arranged in the circumferential direction,
In each segment pair, one segment and the other segment are arranged to face each other in the axial direction,
In the above code path adjustment process,
Each segment pair is moved in the axial direction independently from the other segment pairs, and the axial center line of the segment pair is kept constant, and the axial interval between one segment and the other segment is changed. Tire manufacturing method. Each segment has a contact portion that contacts the bead member, and the circumferential position of one contact portion in the axial direction and the circumferential position of the other contact portion are the same.
In the above code path adjustment process,
The tire manufacturing method according to claim 7, wherein one segment of the segment pair moves in the axial direction, and the other segment moves in the opposite direction to the movement direction of the one segment by the same movement distance as the one segment.

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