JP2021045858A - Manufacturing method of pneumatic tire - Google Patents

Manufacturing method of pneumatic tire Download PDF

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JP2021045858A
JP2021045858A JP2019168450A JP2019168450A JP2021045858A JP 2021045858 A JP2021045858 A JP 2021045858A JP 2019168450 A JP2019168450 A JP 2019168450A JP 2019168450 A JP2019168450 A JP 2019168450A JP 2021045858 A JP2021045858 A JP 2021045858A
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vulcanization
tire
temperature
slowest
mold
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JP7321040B2 (en
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博行 戸堀
Hiroyuki Tohori
博行 戸堀
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Toyo Tire Corp
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Toyo Tire and Rubber Co Ltd
Toyo Tire Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/80—Technologies aiming to reduce greenhouse gasses emissions common to all road transportation technologies
    • Y02T10/86—Optimisation of rolling resistance, e.g. weight reduction 

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Abstract

To provide a manufacturing method of a pneumatic tire that reduces a vulcanization time and significantly improves productivity by reliably determining an endpoint of a vulcanization process for each tire.SOLUTION: The manufacturing method of a pneumatic tire includes a vulcanization step of heating and vulcanizing in a mold an unvulcanized raw tire having a pair of bead portions, sidewall portions extending radially outward from each of the bead portions, and tread portions connecting to the radially outward ends of each of the sidewall portions and constituting a tread surface. The vulcanization step includes a first step of embedding a temperature measuring probe in a slowest vulcanized portion of the raw tire, a second step of acquiring, by the temperature measuring probe, data indicating changes over time in the vulcanization temperature of the slowest portion of the vulcanization, a third step of calculating an integrated equivalent vulcanization amount at the slowest portion of the vulcanization based on the data, and a fourth step of terminating the vulcanization step when the integrated equivalent vulcanization amount becomes 140°C equivalent rheometer vulcanization speed (t50).SELECTED DRAWING: Figure 1

Description

本発明は、一対のビード部と、ビード部の各々からタイヤ径方向外側に延びるサイドウォール部と、サイドウォール部の各々のタイヤ径方向外側端に連なって踏面を構成するトレッド部とを備えた未加硫の生タイヤを、金型内で加熱加硫する加硫工程を含む空気入りタイヤの製造方法に関する。 The present invention includes a pair of bead portions, a sidewall portion extending outward in the tire radial direction from each of the bead portions, and a tread portion that is connected to each tire radial outer end of the sidewall portion to form a tread surface. The present invention relates to a method for producing a pneumatic tire including a vulcanization step of heating and vulcanizing an unvulcanized raw tire in a mold.

ゴム製品である空気入りタイヤを製造する場合、その加硫工程はもっとも時間を要する工程となるため、加硫工程の時間短縮の努力が現在でも行われている。その一方で、加硫工程においてゴム部の加硫が不十分であると、ゴムの加硫反応により発生したエアが加硫ゴム内に残存し、かかる残存エアは製品段階でのタイヤ故障の原因となる場合がある。したがって、通常のタイヤ生産の現場では、季節要因などにより、例えば原料である未加硫の生タイヤの温度、金型内温度、雰囲気温度などがばらつく点を考慮し、加硫工程での全ばらつきを加味した余裕時間を加算して加硫工程に要する時間を設定している。 When manufacturing pneumatic tires, which are rubber products, the vulcanization process is the most time-consuming process, and efforts are still being made to shorten the vulcanization process time. On the other hand, if the rubber part is insufficiently vulcanized in the vulcanization process, the air generated by the vulcanization reaction of the rubber remains in the vulcanized rubber, and such residual air causes tire failure at the product stage. May be. Therefore, in a normal tire production site, considering that the temperature of raw unvulcanized tires, which are raw materials, the temperature inside the mold, the atmospheric temperature, etc., vary depending on seasonal factors, the total variation in the vulcanization process. The time required for the vulcanization process is set by adding the extra time in consideration of.

しかしながら、余裕時間の設定はタイヤの生産性向上の観点からは好ましくなく、タイヤ毎に加硫終了時を決定し、効率良く加硫工程を実行することが望まれていた。 However, setting the margin time is not preferable from the viewpoint of improving the productivity of the tire, and it has been desired to determine the end time of vulcanization for each tire and efficiently execute the vulcanization process.

下記特許文献１には、加硫工程が進行している間に加硫試料のインピーダンスを測定し、加硫試料の高分子抵抗値Ｒｐの増加速度が急激に緩慢になる時点を最適の加硫停止時間とする、加硫試料の実時間加硫調節方法が記載されている。しかしながら、この方法では、加硫試料に対するインピーダンス測定を、２個の電極の間に加硫試料を挟んで測定する必要があり、しかもタイヤは通常、複合材料の積層体であるため、この方法をタイヤ加硫時のタイヤに応用することは困難である。 In Patent Document 1 below, the impedance of a vulcanized sample is measured while the vulcanization process is in progress, and the optimum vulcanization is when the rate of increase in the polymer resistance value Rp of the vulcanized sample suddenly slows down. A method for adjusting the real-time vulcanization of a vulcanized sample as an downtime is described. However, in this method, it is necessary to measure the impedance of the vulcanized sample by sandwiching the vulcanized sample between two electrodes, and since the tire is usually a laminate of composite materials, this method is used. It is difficult to apply it to tires during tire vulcanization.

特開２００３−２１１４５９号公報Japanese Unexamined Patent Publication No. 2003-21459

本発明は上記実情に鑑みてなされたものであり、その目的は、タイヤ毎に加硫工程の終了時点を確実に決定することにより、加硫時間を短縮し、生産性を著しく向上した空気入りタイヤの製造方法を提供することにある。 The present invention has been made in view of the above circumstances, and an object of the present invention is to shorten the vulcanization time and significantly improve productivity by reliably determining the end time point of the vulcanization process for each tire. The purpose is to provide a method for manufacturing tires.

上記目的は、下記の如き本発明により達成できる。即ち本発明は、一対のビード部と、前記ビード部の各々からタイヤ径方向外側に延びるサイドウォール部と、前記サイドウォール部の各々のタイヤ径方向外側端に連なって踏面を構成するトレッド部とを備えた未加硫の生タイヤを、金型内で加熱加硫する加硫工程を含む空気入りタイヤの製造方法であって、前記加硫工程が、前記生タイヤの加硫最遅部に温度測定プローブを埋設する第１段階と、前記温度測定プローブにより、前記加硫最遅部の加硫温度の経時変化を示すデータを取得する第２段階と、前記データに基づき前記加硫最遅部での積算等価加硫量を計算する第３段階と、前記積算等価加硫量が１４０℃換算レオメータ加硫速度（ｔ５０）となった時点で前記加硫工程を終了する第４段階とを備えることを特徴とする空気入りタイヤの製造方法に関する。 The above object can be achieved by the present invention as described below. That is, the present invention includes a pair of bead portions, a sidewall portion extending outward in the tire radial direction from each of the bead portions, and a tread portion that is connected to each tire radial outer end of the sidewall portion to form a tread surface. A method for producing a pneumatic tire including a vulcanization step of heating and vulcanizing an unvulcanized raw tire provided with the above, wherein the vulcanization step is performed at the latest vulcanization portion of the raw tire. The first step of burying the temperature measurement probe, the second step of acquiring data indicating the change over time of the vulcanization temperature of the slowest vulcanization portion by the temperature measurement probe, and the slowest vulcanization based on the data. The third step of calculating the integrated equivalent vulcanization amount in the unit and the fourth step of ending the vulcanization step when the integrated equivalent vulcanization amount reaches the 140 ° C. equivalent leometer vulcanization rate (t50). The present invention relates to a method for manufacturing a pneumatic tire, which is characterized by being provided.

本発明は、空気入りタイヤの加硫工程に特徴があり、第１〜第４段階を少なくとも有する。まず、一対のビード部と、ビード部の各々からタイヤ径方向外側に延びるサイドウォール部と、サイドウォール部の各々のタイヤ径方向外側端に連なって踏面を構成するトレッド部とを備えた未加硫の生タイヤの加硫最遅部に、温度測定プローブを埋設し（第１段階）、該温度測定プローブにより、加硫最遅部の加硫温度の経時変化を示すデータを取得する（第２段階）。次いで、第２工程で取得したデータに基づき加硫最遅部での積算等価加硫量を計算する（第３段階）。そして、計算した積算等価加硫量が１４０℃換算レオメータ加硫速度（ｔ５０）となった時点で加硫工程を終了する（第４段階）。これにより、空気入りタイヤの加硫工程において、容易に加硫終点を見極めることができる。その結果、余分な余裕時間の設定が不要となり、空気入りタイヤの生産性を高めることができる。加えて、空気入りタイヤ１本毎に加硫反応が確実に終了していることが確認できるため、品質保証体制を確立することができる。 The present invention is characterized by a vulcanization step of a pneumatic tire and has at least the first to fourth steps. First, a pair of bead portions, a sidewall portion extending outward in the tire radial direction from each of the bead portions, and a tread portion connected to each tire radial outer end of the sidewall portion to form a tread surface are not added. A temperature measurement probe is embedded in the slowest vulcanization part of the raw vulcanized tire (first stage), and data showing the change over time in the vulcanization temperature of the slowest vulcanization part is acquired by the temperature measurement probe (first stage). 2 steps). Next, the integrated equivalent vulcanization amount in the slowest part of vulcanization is calculated based on the data acquired in the second step (third step). Then, the vulcanization step is terminated when the calculated integrated equivalent vulcanization amount reaches the rheometer vulcanization rate (t50) converted to 140 ° C. (fourth step). Thereby, in the vulcanization process of the pneumatic tire, the vulcanization end point can be easily determined. As a result, it is not necessary to set an extra spare time, and the productivity of the pneumatic tire can be increased. In addition, since it can be confirmed that the vulcanization reaction is surely completed for each pneumatic tire, a quality assurance system can be established.

上記空気入りタイヤの製造方法において、前記温度測定プローブが、プラチナ測温抵抗体であることが好ましい。温度測定プローブの感度が悪い場合、加硫最遅部の加硫温度の経時変化を示すデータの正確性が低下するため、加硫終点の見極めの確度が低下する場合がある。一方、プラチナ測温抵抗体は温度変化に対する感度が非常に高いため、確実に加硫終点を見極めることが可能となるため、空気入りタイヤの生産性をさらに高めることができる。 In the method for manufacturing a pneumatic tire, it is preferable that the temperature measuring probe is a platinum resistance temperature detector. If the sensitivity of the temperature measurement probe is poor, the accuracy of the data indicating the change over time in the vulcanization temperature at the slowest part of vulcanization is reduced, so that the accuracy of determining the vulcanization end point may be reduced. On the other hand, since the platinum resistance temperature detector is extremely sensitive to temperature changes, it is possible to reliably determine the vulcanization end point, and thus the productivity of pneumatic tires can be further increased.

上記空気入りタイヤの製造方法において、前記加硫最遅部が、前記トレッド部のショルダー部であることが好ましい。これにより、空気入りタイヤの加硫終点をより確実に見極めることが可能となり、空気入りタイヤの生産性をさらに高めることができる。 In the method for manufacturing a pneumatic tire, it is preferable that the slowest vulcanization portion is the shoulder portion of the tread portion. This makes it possible to more reliably determine the vulcanization end point of the pneumatic tire, and further increase the productivity of the pneumatic tire.

本発明に係るタイヤの一例を示すタイヤ子午線断面図A tire meridian sectional view showing an example of a tire according to the present invention. タイヤの加硫に用いる金型を概念的に示す断面図Cross-sectional view conceptually showing a mold used for vulcanizing tires

本発明の実施の形態について図面を参照しながら説明する。図１に示した生タイヤ９は、一対のビード部１と、ビード部１の各々からタイヤ径方向外側に延びるサイドウォール部２と、サイドウォール部２の各々のタイヤ径方向外側端に連なって踏面を構成するトレッド部３とを備えた空気入りタイヤである。ビード部１には、環状のビードコア１ａが配されている。 Embodiments of the present invention will be described with reference to the drawings. The raw tire 9 shown in FIG. 1 is connected to a pair of bead portions 1, a sidewall portion 2 extending outward in the tire radial direction from each of the bead portions 1, and each tire radial outer end of the sidewall portion 2. It is a pneumatic tire provided with a tread portion 3 constituting a tread surface. An annular bead core 1a is arranged in the bead portion 1.

カーカス層４は、トレッド部３からサイドウォール部２を経てビード部１に至り、その端部がビードコア１ａを介して折り返されている。カーカス層４は、少なくとも一枚のカーカスプライによって構成される。カーカスプライは、タイヤ周方向に対して略９０°の角度で延びるカーカスコードをトッピングゴムで被覆して形成されている。 The carcass layer 4 reaches the bead portion 1 from the tread portion 3 via the sidewall portion 2, and the end portion thereof is folded back via the bead core 1a. The carcass layer 4 is composed of at least one carcass ply. The carcass ply is formed by covering a carcass cord extending at an angle of approximately 90 ° with respect to the tire circumferential direction with a topping rubber.

ベルト層５は、トレッド部３でカーカス層４の外側に貼り合わされ、トレッドゴム６により外側から覆われている。ベルト層５は、複数枚（本実施形態では二枚）のベルトプライによって構成される。各ベルトプライは、タイヤ周方向に対して傾斜して延びるベルトコードをトッピングゴムで被覆して形成され、該ベルトコードがプライ間で互いに逆向きに交差するように積層されている。 The belt layer 5 is attached to the outside of the carcass layer 4 at the tread portion 3, and is covered from the outside by the tread rubber 6. The belt layer 5 is composed of a plurality of belt plies (two in the present embodiment). Each belt ply is formed by covering a belt cord extending in an inclined direction with respect to the tire circumferential direction with topping rubber, and the belt cords are laminated so as to intersect each other in opposite directions between the plies.

トレッドゴム６は、１層のみで構成しても良く、タイヤ径方向内側のベーストレッドと、その外周側に位置するキャップトレッドとを有する、所謂キャップベース構造で構成しても良い。 The tread rubber 6 may be composed of only one layer, or may be composed of a so-called cap base structure having a base tread on the inner side in the tire radial direction and a cap tread located on the outer peripheral side thereof.

図１に示した生タイヤ９は、未加硫状態の生タイヤであり、後述する加硫工程において、製品タイヤの形状にシェーピングされる（図２参照）とともに、そのトレッド表面には種々のトレッドパターンが形成される。 The raw tire 9 shown in FIG. 1 is a raw tire in an unvulcanized state, and is shaped into the shape of a product tire in a vulcanization step described later (see FIG. 2), and various treads are formed on the tread surface thereof. A pattern is formed.

生タイヤ９の加硫成形では、図２に示すような金型１０が用いられる。この金型１０には、生タイヤ９が未加硫状態のままセットされ、その金型１０内の生タイヤ９に加熱加圧を施すことで加硫工程が行われる。 In the vulcanization molding of the raw tire 9, the mold 10 as shown in FIG. 2 is used. The raw tire 9 is set in the mold 10 in an unvulcanized state, and the vulcanization step is performed by applying heat and pressure to the raw tire 9 in the mold 10.

金型１０は、生タイヤ９の踏面に接するトレッド型部１１と、下方を向いたタイヤ外面に接する下型部１２と、上方を向いたタイヤ外面に接する上型部１３とを備える。これらは、周囲に設置された開閉機構（不図示）によって、型締め状態と金型開放状態との間で変位自在に構成され、かかる開閉機構の構造は周知である。トレッド型部１１はさらに周方向に複数個に分割されており、金型１０内に配設される生タイヤ９の径方向に移動可能となっている。また、金型１０には、電気ヒータや蒸気ジャケットなどの熱源を有するプラテン板（不図示）が設けられており、これによって各型部の加熱が行われる。 The mold 10 includes a tread mold portion 11 in contact with the tread surface of the raw tire 9, a lower mold portion 12 in contact with the tire outer surface facing downward, and an upper mold portion 13 in contact with the tire outer surface facing upward. These are configured to be displaceable between the mold tightening state and the mold open state by an opening / closing mechanism (not shown) installed around them, and the structure of such an opening / closing mechanism is well known. The tread mold portion 11 is further divided into a plurality of parts in the circumferential direction, and is movable in the radial direction of the raw tire 9 arranged in the mold 10. Further, the mold 10 is provided with a platen plate (not shown) having a heat source such as an electric heater or a steam jacket, whereby each mold portion is heated.

金型１０の中心部には、タイヤと同軸状に中心機構１４が設けられ、これの周囲にトレッド型部１１、下型部１２および上型部１３が設置されている。中心機構１４は、ゴム袋状のブラダー１５と、タイヤ軸方向に延びるセンターポスト１６とを有し、センターポスト１６には、ブラダー１５の端部を把持する上部クランプ１７と下部クランプ１８が設けられている。 A central mechanism 14 is provided coaxially with the tire in the central portion of the mold 10, and a tread mold portion 11, a lower mold portion 12, and an upper mold portion 13 are installed around the central mechanism 14. The central mechanism 14 has a rubber bag-shaped bladder 15 and a center post 16 extending in the tire axial direction, and the center post 16 is provided with an upper clamp 17 and a lower clamp 18 for gripping the end portion of the bladder 15. ing.

中心機構１４には、ブラダー１５内への加熱媒体の供給を行うための媒体供給路２１が上下に延設され、その媒体供給路２１の上端に噴出し口２２が形成されている。媒体供給路２１には、加熱媒体供給源２３から供給された加熱媒体や、加圧媒体供給源２６から供給された加圧媒体が流れる供給配管２４が接続されている。加熱媒体は、バルブ２５の開閉操作に応じて供給され、加圧媒体は、バルブ２８の開閉操作に応じて供給される。 In the central mechanism 14, a medium supply path 21 for supplying the heating medium into the bladder 15 is extended vertically, and a ejection port 22 is formed at the upper end of the medium supply path 21. A heating medium supplied from the heating medium supply source 23 and a supply pipe 24 through which the pressurizing medium supplied from the pressurizing medium supply source 26 flows are connected to the medium supply path 21. The heating medium is supplied according to the opening / closing operation of the valve 25, and the pressurizing medium is supplied according to the opening / closing operation of the valve 28.

また、中心機構１４には、ブラダー１５内の加熱媒体と加圧媒体とが混合された高温高圧流体を排出するための媒体排出路３１が上下に延設され、その媒体排出路３１の上端に回収口３２が形成されている。媒体排出路３１には、高温高圧流体が流れる排出配管３４が接続され、その開閉を操作するブローバルブ３３を排出配管３４に設けている。ポンプ３５は、媒体排出路３１を通る高温高圧流体が媒体供給路２１を経由してブラダー１５の内部に再供給されるように、高温高圧流体を強制循環させる手法を用いても構わない。 Further, in the central mechanism 14, a medium discharge path 31 for discharging a high-temperature and high-pressure fluid in which a heating medium and a pressure medium in the bladder 15 are mixed is extended vertically at the upper end of the medium discharge path 31. A collection port 32 is formed. A discharge pipe 34 through which a high-temperature and high-pressure fluid flows is connected to the medium discharge passage 31, and a blow valve 33 for operating the opening / closing of the discharge pipe 34 is provided in the discharge pipe 34. The pump 35 may use a method of forcibly circulating the high-temperature and high-pressure fluid so that the high-temperature and high-pressure fluid passing through the medium discharge path 31 is resupplied to the inside of the bladder 15 via the medium supply path 21.

以下、本発明の製造方法における加硫工程について具体的に説明する。 Hereinafter, the vulcanization step in the production method of the present invention will be specifically described.

まず、図２のように金型１０内に生タイヤ９をセットし、膨張させたブラダー１５によって生タイヤ９を金型１０の内面形状近くまでシェーピングする。これにより、生タイヤ９は、ブラダー１５によって保持され、トレッド型部１１、下型部１２および上型部１３の各々に宛がわれる。この時点で、生タイヤ９の加硫最遅部に温度測定プローブを埋設する（第１段階）。加硫最遅部とは、タイヤの加硫が最も進行し難い部位を意味し、通常はトレッド部３のショルダー部を意味する。特にショルダー部の中でも、加硫後のトレッド部３の内表面の法線に沿って測定される、トレッド部３の厚みが最大になる位置を加硫最遅部とすることが好ましい。いずれにせよ、本発明においては、加硫最遅部における加硫温度を測定するため、温度測定プローブを生タイヤ９の加硫最遅部に埋設する。埋設方法としては、例えば温度測定プローブをトレッド型部１１のショルダー部に対応する位置に配設し、トレッド型部１１が生タイヤ９の径方向に移動して生タイヤ９が宛がわれる際、温度測定プローブが生タイヤ９内に押し込まれつつ埋設されるように設計することが考えられる。このように生タイヤ９内に埋設された温度測定プローブにより、加硫工程時には生タイヤの温度を測定し、加硫工程終了時にはトレッド型部１１を含む金型１０からタイヤを脱型する際に加硫最遅部から温度測定プローブを同時に抜き取れば良い。 First, as shown in FIG. 2, the raw tire 9 is set in the mold 10, and the raw tire 9 is shaped to be close to the inner surface shape of the mold 10 by the expanded bladder 15. As a result, the raw tire 9 is held by the bladder 15 and addressed to each of the tread mold portion 11, the lower mold portion 12, and the upper mold portion 13. At this point, the temperature measuring probe is embedded in the slowest part of the vulcanization of the raw tire 9 (first stage). The slowest vulcanization portion means a portion where vulcanization of the tire is most difficult to proceed, and usually means a shoulder portion of the tread portion 3. In particular, among the shoulder portions, the position where the thickness of the tread portion 3 is maximized, which is measured along the normal of the inner surface of the tread portion 3 after vulcanization, is preferably the slowest vulcanization portion. In any case, in the present invention, in order to measure the vulcanization temperature in the slowest vulcanization portion, the temperature measuring probe is embedded in the slowest vulcanization portion of the raw tire 9. As an embedding method, for example, when a temperature measuring probe is arranged at a position corresponding to the shoulder portion of the tread mold portion 11 and the tread mold portion 11 moves in the radial direction of the raw tire 9 and the raw tire 9 is addressed. It is conceivable to design the temperature measuring probe so that it is embedded while being pushed into the raw tire 9. With the temperature measuring probe embedded in the raw tire 9 in this way, the temperature of the raw tire is measured at the time of the vulcanization process, and at the end of the vulcanization process, when the tire is removed from the mold 10 including the tread mold portion 11. The temperature measuring probe may be extracted from the slowest part of the vulcanization at the same time.

本発明において、加硫温度を測定する際に使用する温度測定プローブとして、金属の電気抵抗が温度変化に対して変化する性質を利用した測温抵抗体を使用することができる。かかる金属としては、プラチナ、ニッケル、および銅などが例示可能であるが、本発明においては、温度変化に対する抵抗値変化（感度）が大きく、その結果、温度変化に対する感度が非常に高いプラチナ測温抵抗体を特に好適に使用することができる。 In the present invention, as a temperature measuring probe used when measuring the vulcanization temperature, a resistance temperature measuring resistor utilizing the property that the electric resistance of a metal changes with respect to a temperature change can be used. Examples of such metals include platinum, nickel, and copper, but in the present invention, the resistance value change (sensitivity) to a temperature change is large, and as a result, the platinum temperature measurement is extremely sensitive to a temperature change. Resistors can be used particularly preferably.

続いて、金型１０を加熱して生タイヤ９をタイヤ外面側から加熱する外側加熱と、金型１０内のブラダー１５に高温の加熱媒体を供給して生タイヤ９をタイヤ内面側から加熱する内側加熱とからなる加熱を行い、生タイヤ９の加硫を実行する。金型１０は、上記の蒸気ジャケットなどにより予め加熱されていて、これにより外側加熱が行われる。内側加熱は、タイヤ９のシェーピング後に、媒体供給路２１を通じてブラダー１５内に加熱媒体を供給することで行われる。加熱媒体を所定時間供給した後、引き続いてブラダー１５内に加圧媒体を供給し、タイヤ９を高圧で加圧する。加熱媒体としては、例えばスチームや高温水が使用され、加圧媒体としては、例えば窒素ガスなどの不活性ガスやスチームが使用される。 Subsequently, the mold 10 is heated to heat the raw tire 9 from the tire outer surface side, and the bladder 15 in the mold 10 is supplied with a high temperature heating medium to heat the raw tire 9 from the tire inner surface side. The raw tire 9 is vulcanized by heating including the inner heating. The mold 10 is preheated by the steam jacket or the like described above, whereby the outside heating is performed. The inner heating is performed by supplying the heating medium into the bladder 15 through the medium supply path 21 after shaping the tire 9. After supplying the heating medium for a predetermined time, the pressurizing medium is subsequently supplied into the bladder 15 to pressurize the tire 9 at a high pressure. As the heating medium, for example, steam or high-temperature water is used, and as the pressurizing medium, for example, an inert gas such as nitrogen gas or steam is used.

加硫工程において、外側加熱時の金型１０の温度は１２５〜１６５℃に設定することが好ましく、内側加熱時のブラダー１５の温度も１２５〜１６５℃に設定することが好ましい。さらに、未加硫の生タイヤ９を金型１０内で加熱加硫する際、外側加熱時の金型１０の温度Ｔｍと内側加熱時のブラダー１５の温度Ｔｂとの比（Ｔｍ／Ｔｂ）を０．７５〜１に設定することが好ましく、０．８〜０．９８に設定することがより好ましい。 In the vulcanization step, the temperature of the mold 10 during outer heating is preferably set to 125 to 165 ° C, and the temperature of the bladder 15 during inner heating is also preferably set to 125 to 165 ° C. Further, when the unvulcanized raw tire 9 is heated and vulcanized in the mold 10, the ratio (Tm / Tb) of the temperature Tm of the mold 10 when heated outside and the temperature Tb of the bladder 15 when heated inside is determined. It is preferably set to 0.75 to 1, and more preferably 0.8 to 0.98.

第２段階では、温度測定プローブにより、加硫最遅部の温度の経時変化を示すデータを取得する。例えば、金型１０内に生タイヤ９がセットされた時点から所定の時間間隔で加硫最遅部の温度を測定する。温度を測定する時間間隔としては３０秒以下の時間間隔が好ましく、１０秒以下の時間間隔がより好ましい。 In the second stage, the temperature measuring probe is used to acquire data showing the time course of the temperature of the slowest part of vulcanization. For example, the temperature of the slowest part of vulcanization is measured at predetermined time intervals from the time when the raw tire 9 is set in the mold 10. As the time interval for measuring the temperature, a time interval of 30 seconds or less is preferable, and a time interval of 10 seconds or less is more preferable.

第３段階では、第２工程で取得したデータに基づき加硫最遅部での積算等価加硫量を計算する。積算等価加硫量は、Ｖａｎ’ｔＨｏｆｆの法則に基づく下記の加硫反応速度式から換算される加硫時間ｔ０の積算値であり、単位は（分）である。ここで、Ｔは実際の加硫温度（℃）、ｔは加硫温度Ｔでの加硫時間（分）、Ｔ０は基準温度（℃）、ｔ０は基準温度Ｔ０での加硫時間（分）、αは加硫温度係数（加硫温度が１０℃変わるときの加硫の速さが変わる割合）である。基準温度Ｔ０には１４０℃を採用し、加硫温度係数αには、２またはこれに近い値を任意に採用しうるが、簡便法としてα＝２を採用する。
ｔ０＝ｔ×α（Ｔ−Ｔ０）／１０ In the third step, the integrated equivalent vulcanization amount in the slowest part of vulcanization is calculated based on the data acquired in the second step. The integrated equivalent vulcanization amount is an integrated value of the vulcanization time t 0 converted from the following vulcanization reaction rate equation based on Van't Hoff's law, and the unit is (minutes). Here, T is the actual vulcanization temperature (° C.), t is the vulcanization time (minutes) at the vulcanization temperature T, T 0 is the reference temperature (° C.), and t 0 is the vulcanization time at the reference temperature T 0. (Minute), α is the vulcanization temperature coefficient (the rate at which the vulcanization speed changes when the vulcanization temperature changes by 10 ° C.). 140 ° C. is adopted as the reference temperature T 0 , and 2 or a value close to this can be arbitrarily adopted as the vulcanization temperature coefficient α, but α = 2 is adopted as a simple method.
t 0 = t × α (T-T0) / 10

第４段階では、計算した積算等価加硫量が１４０℃換算レオメータ加硫速度（ｔ５０）となった時点で加硫工程を終了する。「１４０℃換算レオメータ加硫速度」とは、ＪＩＳ Ｋ６３００−２：２０１３に準拠した加硫速度（ｔ５０）であり、ｔ５０は、レオメータによる未加硫ゴム組成物の加硫挙動測定試験において、トルクの最大値をＭＨ、最小値をＭＬとしたときにトルクが（ＭＨ−ＭＬ）の５０％になるまでの測定開始からの時間（分）である。１４０℃換算レオメータ加硫速度（ｔ５０）は、生タイヤの加硫最遅部のゴム配合に基づき、予め測定しておくことが可能である。加硫最遅部のゴム配合の加硫速度は、例えば、加硫促進剤の添加量によって調整できる。金型１０内に生タイヤ９がセットされた時点から加硫を開始し、第３段階で計算する積算等価加硫量（分）がｔ５０（分）となった時点で、加硫工程を終了する。 In the fourth stage, the vulcanization step is terminated when the calculated integrated equivalent vulcanization amount reaches the rheometer vulcanization rate (t50) converted to 140 ° C. The "140 ° C.-converted leometer vulcanization rate" is a vulcanization rate (t50) based on JIS K6300-2: 2013, and t50 is a torque in a vulcanization behavior measurement test of an unvulcanized rubber composition using a leometer. It is the time (minutes) from the start of measurement until the torque becomes 50% of (MH-ML) when the maximum value of is MH and the minimum value is ML. The 140 ° C.-converted rheometer vulcanization rate (t50) can be measured in advance based on the rubber composition of the slowest vulcanization portion of the raw tire. The vulcanization rate of the rubber compound in the slowest part of vulcanization can be adjusted by, for example, the amount of the vulcanization accelerator added. Vulcanization starts when the raw tire 9 is set in the mold 10, and ends when the cumulative equivalent vulcanization amount (minutes) calculated in the third stage reaches t50 (minutes). To do.

加硫工程終了後は、金型１０を解放状態としつつ、金型１０内に配設した温度測定プローブを加硫済タイヤから抜き取る。その結果、タイヤ毎に加硫終点を見極め、加硫時間を短縮しつつ空気入りタイヤを製造することができる。 After the vulcanization step is completed, the temperature measuring probe arranged in the mold 10 is pulled out from the vulcanized tire while the mold 10 is in the open state. As a result, it is possible to identify the vulcanization end point for each tire and manufacture a pneumatic tire while shortening the vulcanization time.

本発明は上述した実施形態に何ら限定されるものではなく、本発明の趣旨を逸脱しない範囲内で種々の改良変更が可能である。 The present invention is not limited to the above-described embodiment, and various improvements and changes can be made without departing from the spirit of the present invention.

実施例１〜３、比較例１〜２
サンプルタイヤ（タイヤサイズ：２７５／７０Ｒ２２．５）を製造するための生タイヤとしては、ショルダー部（加硫最遅部）のゴム配合が、１４０℃換算レオメータ加硫速度（ｔ５０）で１６（分）、（ｔ７０）で１８（分）、（ｔ９０）で２２（分）となるものを使用した。 Examples 1-3, Comparative Examples 1-2
As a raw tire for manufacturing a sample tire (tire size: 275 / 70R22.5), the rubber compounding of the shoulder part (the slowest part of vulcanization) is 16 (minutes) at a rheometer vulcanization rate (t50) converted to 140 ° C. ), (T70) is 18 (minutes), and (t90) is 22 (minutes).

図２に記載の加硫金型１０を用いて、サンプルタイヤの加硫を実施した。その際、高精度デジタルデータロガー（Ｆｌｕｋｅ社製、商品名「１５８６Ａ」）に接続されたプラチナ測温抵抗体（山里産業社製 「細管型測温抵抗体」）を金型１０内であって、空気入りタイヤのショルダー部に対応する位置に配設した。 The sample tire was vulcanized using the vulcanization die 10 shown in FIG. At that time, a platinum resistance temperature detector (“thin tube resistance temperature detector” manufactured by Yamazato Sangyo Co., Ltd.) connected to a high-precision digital data logger (Fluke, trade name “1586A”) was placed in the mold 10. , Arranged at a position corresponding to the shoulder portion of the pneumatic tire.

各実施例および比較例に係る製造方法を実施した際の外側加熱時の金型１０の温度および内側加熱時のブラダー１５の温度を表１に示す。 Table 1 shows the temperature of the mold 10 when the outer side is heated and the temperature of the bladder 15 when the inner side is heated when the manufacturing methods according to each example and the comparative example are carried out.

比較例１は、従来公知の製造方法に対応し、加硫工程での全ばらつきを加味した余裕時間を加算して加硫工程を実施した。実施例１〜３については、金型１０内に生タイヤ９がセットされた時点から加硫を開始し、第３段階で計算する積算等価加硫量（分）がｔ５０（分）となった時点で、加硫工程を終了した。比較例２については、金型１０内に生タイヤ９がセットされた時点から加硫を開始し、第３段階で計算する積算等価加硫量（分）がｔ９０（分）となった時点で、金型１０を開放し、加硫工程を終了した。 Comparative Example 1 corresponded to a conventionally known production method, and the vulcanization step was carried out by adding a margin time in consideration of all variations in the vulcanization step. In Examples 1 to 3, vulcanization was started from the time when the raw tire 9 was set in the mold 10, and the cumulative equivalent vulcanization amount (minutes) calculated in the third step was t50 (minutes). At this point, the vulcanization process was completed. In Comparative Example 2, vulcanization was started when the raw tire 9 was set in the mold 10, and when the cumulative equivalent vulcanization amount (minutes) calculated in the third stage reached t90 (minutes). , The mold 10 was opened, and the vulcanization process was completed.

前記サンプルタイヤの生産性（加硫生産性）については、以下の基準で評価した。 The productivity (vulcanization productivity) of the sample tire was evaluated according to the following criteria.

［加硫生産性］
金型１０内に生タイヤ９がセットされた時点から、金型１０を開放状態し、加硫工程を終了した時点までを加硫時間と定義し、比較例１での加硫時間を１００とする指数で表した。数値が低いほど加硫生産性に優れることを意味する。結果を表１に示す。 [Vulcanization productivity]
The vulcanization time is defined as the time from when the raw tire 9 is set in the mold 10 to the time when the mold 10 is opened and the vulcanization process is completed, and the vulcanization time in Comparative Example 1 is 100. Expressed as an index. The lower the value, the better the vulcanization productivity. The results are shown in Table 1.

製造したサンプルタイヤのタイヤ転がり抵抗を測定し、以下の基準で評価した。 The tire rolling resistance of the manufactured sample tire was measured and evaluated according to the following criteria.

［タイヤ転がり抵抗］
タイヤ転がり抵抗は、製造したサンプルタイヤを標準リムに空気圧２００ｋＰａでリム組みし、転がり抵抗測定用の１軸ドラム試験機を使用し、負荷荷重３．９２ｋＮ、時速６０ｋｍでの転がり抵抗を測定した。比較例１を１００とする指数で表し、数値が小さいほど転がり抵抗が低く燃費性能に優れることを示す。結果を表１に示す。 [Tire rolling resistance]
For the tire rolling resistance, the manufactured sample tire was assembled on a standard rim at an air pressure of 200 kPa, and a uniaxial drum tester for measuring rolling resistance was used to measure the rolling resistance at a load load of 3.92 kN and a speed of 60 km / h. Comparative Example 1 is represented by an index of 100, and the smaller the value, the lower the rolling resistance and the better the fuel efficiency. The results are shown in Table 1.

Figure 2021045858
Figure 2021045858

表１の結果から、従来公知の製造方法に比して、実施例１〜３の製造方法では、加硫時間を大幅に短縮しつつ、タイヤ転がり抵抗の悪化が抑制された空気入りタイヤを製造できることがわかる。一方、積算等価加硫量（分）がｔ９０（分）となった時点で、加硫工程を終了した比較例２では、加硫生産性は向上するものの、空気入りタイヤのタイヤ転がり抵抗が悪化することがわかる。 From the results in Table 1, in the manufacturing methods of Examples 1 to 3 as compared with the conventionally known manufacturing methods, pneumatic tires in which deterioration of tire rolling resistance is suppressed while significantly shortening the vulcanization time are manufactured. I know I can do it. On the other hand, in Comparative Example 2 in which the vulcanization step was completed when the integrated equivalent vulcanization amount (minutes) reached t90 (minutes), the vulcanization productivity was improved, but the tire rolling resistance of the pneumatic tire deteriorated. You can see that it does.

１ ビード部
２ サイドウォール部
３ トレッド部
４ カーカス層
５ ベルト層
６ トレッドゴム
９ 生タイヤ
１０ 金型
１５ ブラダー 1 bead part 2 sidewall part 3 tread part 4 carcass layer 5 belt layer 6 tread rubber 9 raw tire 10 mold 15 bladder

Claims (3)

一対のビード部と、前記ビード部の各々からタイヤ径方向外側に延びるサイドウォール部と、前記サイドウォール部の各々のタイヤ径方向外側端に連なって踏面を構成するトレッド部とを備えた未加硫の生タイヤを、金型内で加熱加硫する加硫工程を含む空気入りタイヤの製造方法であって、
前記加硫工程が、前記生タイヤの加硫最遅部に温度測定プローブを埋設する第１段階と、前記温度測定プローブにより、前記加硫最遅部の加硫温度の経時変化を示すデータを取得する第２段階と、前記データに基づき前記加硫最遅部での積算等価加硫量を計算する第３段階と、前記積算等価加硫量が１４０℃換算レオメータ加硫速度（ｔ５０）となった時点で前記加硫工程を終了する第４段階とを備えることを特徴とする空気入りタイヤの製造方法。 A pair of bead portions, a sidewall portion extending outward in the tire radial direction from each of the bead portions, and a tread portion connected to each tire radial outer end of the sidewall portion to form a tread surface are not added. A method for producing a pneumatic tire, which includes a vulcanization step of heating and vulcanizing a raw vulcanized tire in a mold.
In the vulcanization step, the first step of embedding a temperature measuring probe in the slowest vulcanization portion of the raw tire and the data showing the time course of the vulcanization temperature of the slowest vulcanization portion by the temperature measuring probe are obtained. The second step to be acquired, the third step of calculating the integrated equivalent vulcanization amount in the slowest part of vulcanization based on the data, and the integrated equivalent vulcanization amount being the 140 ° C. equivalent leometer vulcanization rate (t50). A method for producing a pneumatic tire, which comprises a fourth step of terminating the vulcanization step at the time when the vulcanization step is completed. 前記温度測定プローブが、プラチナ測温抵抗体である請求項１に記載の空気入りタイヤの製造方法。 The method for manufacturing a pneumatic tire according to claim 1, wherein the temperature measuring probe is a platinum resistance temperature detector. 前記加硫最遅部が、前記トレッド部のショルダー部である請求項１または２に記載の空気入りタイヤの製造方法。 The method for manufacturing a pneumatic tire according to claim 1 or 2, wherein the slowest vulcanization portion is a shoulder portion of the tread portion.
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JP2019107784A (en) * 2017-12-15 2019-07-04 Ｔｏｙｏ Ｔｉｒｅ株式会社 Method for manufacturing pneumatic tire

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JP2005271534A (en) * 2004-03-26 2005-10-06 Yokohama Rubber Co Ltd:The Vulcanizing method of pneumatic tire
JP2018062149A (en) * 2016-10-14 2018-04-19 横浜ゴム株式会社 Vulcanization method of pneumatic tire
JP2019107784A (en) * 2017-12-15 2019-07-04 Ｔｏｙｏ Ｔｉｒｅ株式会社 Method for manufacturing pneumatic tire

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