JP2019098602A - Method for simulating vulcanization of green tire - Google Patents

Abstract

To determine the presence/absence of bitten rubber.SOLUTION: There is provided a method using a computer for simulating the vulcanization molding of a green tire with a mold. The simulation method comprises a step S1 where a mold model is input in a computer, the mold metal including a first mold piece model and a second mold piece model which are respectively given through discretizing a first metal piece and a second metal piece by using a finite number of elements; a step S3 where a green tire model given through discretizing a green tire by using a finite number of elements is input in the computer; a step S4 where the computer arranges the green tire model in a cavity of the mold model with the first mold piece model and the second metal piece model being open; a step S6 where the computer begins closing the mold model so that the first metal piece model and the second metal piece model gradually come close to each other; and a step where, during the closing of the mold model, the computer determines whether part of the green tire model is bitten or not between the first mold piece model and the second metal piece model.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a simulation method for simulating how a green tire is vulcanized and formed with a mold using a computer.

  Patent Document 1 below proposes a method for manufacturing a tire in which a green tire is vulcanized with a mold. The mold includes an upper mold for molding a tread portion of a tire and left and right side molds for molding a bead portion from a sidewall portion. These upper molds and left and right side molds are arranged to be openable and closable.

JP, 2008-074013, A

  When the mold is closed after the green tire is inserted into the mold, so-called rubber biting may occur in which a part of the outer surface of the green tire is pinched between the upper mold and the side mold. The pinched rubber remains in the mold as burnt rubber and adheres to the tire which is then vulcanized and molded, resulting in molding failure. When such rubber biting occurs, it is necessary to change the design of the mold and the like, and there is a problem that a lot of time and cost are required.

  The present invention has been made in view of the above-described actual situation, and has as its main object to provide a green tire vulcanization simulation method capable of determining the presence or absence of rubber biting.

  The present invention includes at least a first mold piece and a second mold piece arranged openably and closably, and a molding surface which covers the first mold piece and the second mold piece by closing. A simulation method for simulating, using a computer, how a green tire is vulcanized and formed with a mold forming a partitioned cavity, the computer comprising: the first mold piece and the second mold Inputting a mold model including a first mold piece model and a second mold piece model in which pieces are respectively discretized with a finite number of elements; and discretizing the green tire with a finite number of elements in the computer Inputting the raw tire model, and the computer places the green tire model in the cavity of the mold model with the first mold piece model and the second mold piece model opened. Process and the computer In the process of closing the mold model so that the first mold piece model and the second mold piece model gradually approach each other, and in the process of closing the mold model Determining whether a part of the green tire model is caught between the first mold piece model and the second mold piece model.

  In the method of simulating vulcanization of a green tire according to the present invention, the first mold piece model and the second mold piece model have mating surfaces that contact each other when the mold model is closed, The step of determining may be performed by checking whether the element of the green tire model is in contact with the mating surface.

  In the method of simulating vulcanization of a green tire according to the present invention, in the step of closing the mold model, when it is determined that the element of the green tire model is in contact with the mating surface, the first step The approach between the mold piece model and the second mold piece model may be interrupted.

  In the method of simulating vulcanization of a green tire according to the present invention, the green tire includes a plurality of members joined together, and in the step of inputting the green tire model, the members are separated into a finite number of elements. The component models may be joined together to define the green tire model.

  In the method of simulating vulcanization of a green tire according to the present invention, a bladder model in which a bladder for pressing the green tire to the mold side by expansion in a lumen of the green tire is discretized with a finite number of elements. And the step of closing the mold includes pressing the green tire model toward the first mold piece model and the second mold piece model by expansion deformation of the bladder model. A step may be included.

  The method for simulating vulcanization of a green tire according to the present invention comprises the steps of: disposing a green tire model in a cavity of a mold model in a state in which a first mold piece model and a second mold piece model are open; Closing the mold model so that the mold piece model and the second mold piece model gradually approach each other. Furthermore, in the method for simulating vulcanization of a green tire according to the present invention, in the process of closing the mold model, the green tire model of the green tire model is provided between the first mold piece model and the second mold piece model. It includes the step of determining whether a part is caught. Therefore, the vulcanization simulation according to the present invention uses a computer to determine the presence or absence of so-called rubber bite in which a part of the green tire is sandwiched between the first mold piece and the second mold piece. can do.

It is a perspective view which shows an example of the computer 1 for performing the vulcanization | cure simulation method of a green tire. It is a sectional view showing an example of a green tire. It is sectional drawing explaining a mode that a green tire is vulcanized. It is a flowchart which shows an example of the process sequence of the vulcanization | cure simulation method of a green tire. It is a conceptual diagram which shows an example of a die model and a bladder model. It is a flowchart which shows an example of the process sequence of a raw tire model input process. It is a conceptual diagram which shows an example of a member model. It is a flowchart explaining an example of the process sequence of a joining process. It is a conceptual diagram which shows an example of the member model which has an overlap part. It is a conceptual diagram which shows an example of the member model after a deformation | transformation. It is a conceptual diagram which shows an example of the member model stuck. It is a conceptual diagram which shows an example of the casing model bulged to the radial outside. It is a conceptual diagram which shows an example of the deformed tread ring model. It is a conceptual diagram which shows an example of a raw tire model. It is a conceptual diagram which shows an example of the raw tire model arrange | positioned in the cavity of a mold model. It is a flowchart which shows an example of the process sequence of a die closing process. It is a conceptual diagram explaining the state which closed the 1st mold piece model and the 2nd mold piece model. It is a conceptual diagram explaining the state where a part of green tire model was pinched between the 1st mold piece model and the 2nd mold piece model. It is a conceptual diagram which shows the process in which the design-changed metal mold model is closing.

Hereinafter, an embodiment of the present invention will be described based on the drawings.
The method of simulating the vulcanization of a green tire according to the present embodiment (hereinafter sometimes referred to simply as "the method of simulating vulcanization") simulates how a green tire is vulcanized and formed with a mold using a computer. It is a thing.

  FIG. 1 is a perspective view showing an example of a computer 1 for executing a method of simulating vulcanization of a green tire. The computer 1 includes a main body 1a, a keyboard 1b, a mouse 1c, and a display device 1d. The main body 1a is provided with an arithmetic processing unit (CPU), a ROM, a working memory, a storage device such as a magnetic disk, and disk drive devices 1a1 and 1a2. In the storage device, a processing procedure (program) for executing the vulcanization simulation method of the present embodiment is stored in advance.

  FIG. 2 is a cross-sectional view showing an example of a green tire. The green tire 2 includes a plurality of members 3 joined together. The member 3 includes a tread rubber 3a, sidewall rubber 3b, clinch rubber 3c, bead apex rubber 3d, inner liner rubber 3e, bead core 3f, carcass ply 3g, inner belt ply 3h, outer belt ply 3i, covering rubber 3j, and cushions. Contains rubber 3k. These members 3 are in an unvulcanized state. Here, unvulcanized includes all aspects which have not been completely vulcanized, and the so-called semi-vulcanized state is included in this "unvulcanized".

  The tread rubber 3 a is disposed outside the outer belt ply 3 i in the tread portion 2 a of the green tire 2. The sidewall rubber 3 b is disposed outside the carcass ply 3 g in the sidewall portion 2 b of the green tire 2. The clinch rubber 3c is fixed on the inner side in the tire radial direction of the sidewall rubber 3b. The bead apex rubber 3d extends outward in the tire radial direction from the bead core 3f. The inner liner rubber 3e is disposed on the inner surface of the carcass ply 3g. The cushion rubber 3 k is disposed at the buttress portion of the green tire 2 outside the carcass ply 3 g.

  The bead core 3 f is formed, for example, by spirally winding a steel bead wire to form an approximately rectangular cross-section, and covering the unvulcanized rubber.

  The carcass ply 3g extends from the tread portion 2a to the bead core 3f of the bead portion 2c through the sidewall portion 2b. The carcass ply 3g is formed by covering carcass cords (not shown) arranged at an angle of 75 to 90 degrees with respect to the tire equator C, for example, with unvulcanized topping rubber (not shown). .

  The inner belt ply 3h and the outer belt ply 3i are belt cords (not shown) arranged at an angle of, for example, 10 to 40 degrees with respect to the circumferential direction of the tire (not shown). It is formed by covering with.

  The covering rubber 3j covers both ends of the inner belt ply 3h and both ends of the outer belt ply 3i. The covering rubber 3j of the present embodiment is formed in a U-shaped cross section.

  These members 3 are formed in an annular shape with a forming drum (not shown) or the like in the same way as the conventional green tire 2 molding process, and the green tire 2 is molded by laminating them.

  FIG. 3 is a cross-sectional view for explaining how the green tire 2 is vulcanized. A mold 6 is used for vulcanization of the green tire 2. The mold 6 includes at least a first mold piece 7 and a pair of second mold pieces 8. Furthermore, for vulcanization of the green tire 2 of the present embodiment, a bladder 10 made of an elastic body is used. Note that, instead of the bladder 10, an annular rigid core or the like (not shown) having the molding surface of the green tire 2 on the outer surface may be used.

  The first mold piece 7 has a tread molding surface 11 a capable of molding the tread portion of the tire. On the other hand, the second mold piece 8 has a side molding surface 11 b capable of molding the sidewall portion and the bead portion of the tire.

  The mold 6 of this embodiment can move the first mold piece 7 in and out in the tire radial direction. Further, the mold 6 can move the second mold piece 8 in and out in the tire axial direction. Thereby, the 1st mold piece 7 and the 2nd mold piece 8 are arranged so that opening and closing is possible. By closing the first mold piece 7 and the second mold piece 8 in the mold 6, a cavity defined by the molding surface 11 straddling the first mold piece 7 and the second mold piece 8 is formed. Ru.

  In the step of vulcanizing the green tire 2, first, the green tire 2 is put into the mold 6 in which the first mold piece 7 and the second mold piece 8 are opened. Next, the first mold piece 7 and the second mold piece 8 are closed. Then, due to the expansion of the bladder 10 in the lumen of the green tire 2, the green tire 2 is pressed to the mold 6 side and heated. Thereby, the green tire 2 is vulcanized and molded, and a tire (not shown) is manufactured.

  By the way, when the mold 6 is closed, so-called rubber biting occurs in which a part of the outer surface of the green tire 2 is pinched in the portion 9 between the first mold piece 7 and the second mold piece 8 There is a case. The pinched rubber remains in the mold 6 as burnt rubber and adheres to the tire which is then vulcanized and molded, resulting in molding failure. When such rubber biting occurs, design change of the mold 6 or the like is required, and there is a problem that much time and cost are required.

  In the vulcanization simulation method of the present embodiment, the computer 1 is used to determine the presence or absence of rubber biting. FIG. 4 is a flowchart showing an example of a processing procedure of a method of simulating vulcanization of a green tire.

  In the vulcanization simulation method of the present embodiment, the mold model 16 is input to the computer 1 (step S1). The mold model 16 includes a first mold piece model 17 and a second mold piece model 18 in which the first mold piece 7 and the second mold piece 8 are respectively discretized with a finite number of elements. FIG. 5 is a conceptual view showing an example of the mold model 16 and the bladder model 20. As shown in FIG.

  In step S1, based on information (design data etc.) regarding the mold 6 (shown in FIG. 3), discrete elements F (i) (i = 1, 2,...) Which can be handled by numerical analysis are used. It is Thereby, the mold model 16 including the three-dimensional first mold piece model 17 and the second mold piece model 18 is set. The design data of the mold 6 includes, for example, numerical data such as the cross-sectional shape of the mold 6 and the like.

  As a numerical analysis method, for example, a finite element method, a finite volume method, a difference method or a boundary element method can be adopted as appropriate, but in the present embodiment, the finite element method is adopted. The element F (i) is defined as a three-dimensional solid element. Each element F (i) has a plurality of nodes 22. For each element F (i), numerical data such as the element number, the number of the node 22, the coordinate value of the node 22, and the material characteristics of the mold 6 (for example, density, Young's modulus and / or damping coefficient) are defined Be done.

  The first mold piece model 17 and the second mold piece model 18 of the present embodiment are formed in a thin plate shape having a thickness in the tire circumferential direction. Similar to the first mold piece 7 shown in FIG. 3, the first mold piece model 17 has a tread molding surface 21 a. On the other hand, the second mold piece model 18 has a side molding surface 21 b in the same manner as the second mold piece 8.

  The first mold piece model 17 and the second mold piece model 18 are set to be openable (degradable) similarly to the first mold piece 7 and the second mold piece 8 shown in FIG. . The mold model 16 is divided by the molding surface 21 straddling the first mold piece model 17 and the second mold piece model 18 by closing the first mold piece model 17 and the second mold piece model 18. The cavity is formed. The first mold piece model 17 and the second mold piece model 18 respectively have mating surfaces 31 and 32 which contact each other when the mold model 16 is closed. The mold model 16 is stored in the computer 1.

  In the vulcanization simulation method of this embodiment, a bladder model 20 obtained by discretizing the bladder 10 (shown in FIG. 3) with a finite number of elements is input to the computer 1 (step S2). In step S2, on the basis of information (design data and the like) related to the bladder 10, discretization is performed using a finite number of elements G (i) (i = 1, 2,...) That can be handled by a numerical analysis method. Thereby, a three-dimensional bladder model 20 is set. The design data of the bladder 10 includes, for example, numerical data such as the cross-sectional shape of the bladder 10 and the like.

  As the numerical analysis method, the same one as the element G (i) is adopted. The element G (i) is defined as a three-dimensional solid element. Element G (i) defines numerical data such as element number, node number, coordinate value of node 33, and material properties of bladder 10 (eg, density, Young's modulus, and / or damping coefficient). . Similar to the first mold piece model 17 and the second mold piece model 18, the bladder model 20 has a thickness in the tire circumferential direction. The bladder model 20 is stored in the computer 1.

  Next, in the vulcanization simulation method of the present embodiment, a raw tire model obtained by discretizing the raw tire 2 with a finite number of elements is input to the computer 1 (raw tire model input step S3). FIG. 6 is a flow chart showing an example of the processing procedure of the raw tire model input step S3.

  In the raw tire model input step S3 of the present embodiment, first, a member model 13 is defined in which each member 3 shown in FIG. 2 is discretized with a finite number of elements H (i) (i = 1, 2,...) (Step S31). FIG. 7 is a conceptual view showing an example of the member model 13.

  In step S31, design data (for example, CAD data) of each of the members 3a to 3k before the green tire 2 shown in FIG. 2 is formed is input to the computer 1. The design data includes, for example, numerical data such as the cross-sectional shape of the member 3 and the like. Then, in step S31, the three-dimensional member model 13 is set by discretizing with the finite number of elements H (i) that can be handled by the numerical analysis method based on the design data of the member 3.

  The member model 13 includes a tread rubber model 13a obtained by discretizing the tread rubber 3a (shown in FIG. 2), a sidewall rubber model 13b obtained by discretizing the sidewall rubber 3b (shown in FIG. 2), and a clinch rubber 3c (see FIG. 2) includes a clinched rubber model 13c obtained by discretizing. Further, the member model 13 includes a bead apex rubber model 13d obtained by discretizing the bead apex rubber 3d (shown in FIG. 2), an inner liner rubber model 13e obtained by discretizing the inner liner rubber 3e (shown in FIG. 2), and a bead core 3f (shown in FIG. 2) is discretized to include a bead core model 13f.

  Further, the member model 13 includes a carcass ply model 13g obtained by discretizing the carcass ply 3g (shown in FIG. 2), an inner belt ply model 13h obtained by discretizing the inner belt ply 3h (shown in FIG. 2), and an outer belt ply 3i. A discretized outer belt ply model 13i and a cushion rubber model 13k obtained by discretizing a cushion rubber 3k (shown in FIG. 2) are included. A covering rubber model 13j obtained by discretizing a covering rubber 3j (shown in FIG. 2) is set at the end of the inner belt ply model 13h and the end of the outer belt ply model 13i.

  In the present embodiment, the tread rubber model 13a, sidewall rubber model 13b, clinch rubber model 13c, bead apex rubber model 13d, inner liner rubber model 13e, carcass ply model 13g, inner belt ply model 13h, outer belt ply model 13i, The ends of the covering rubber model 13 j and the cushion rubber model 13 k are respectively formed in a tapered shape.

  As the numerical analysis method, the same one as the element F (i) is adopted. The elements H (i) are defined as three-dimensional solid elements or beam elements. In the element H (i), numerical data such as the element number, the number of the node 34, the coordinate value of the node 34, and the characteristics of the member 3 (for example, density, Young's modulus and / or damping coefficient) are defined. The member model 13 has a thickness in the tire circumferential direction, similarly to the first mold piece model 17 and the second mold piece model 18 shown in FIG. 5. The member model 13 is stored in the computer 1.

  The material properties of the part constituting the unvulcanized rubber in the member model 13 are described, for example, in the literature (H. H., "The large deformation behavior of the unvulcanized rubber under a constant elongation rate", Journal of The Rheological Society of Japan Japan Society of Rheology, 1976, Vol. 4, p. 3-9), literature (Koyuki Tozaki, 3 others, "green strength index, viscoelastic treatment of yield stress", Journal of the Japan Rubber Association, It is disclosed in the general incorporated association Japan Rubber Association, 1969, 42, 6, p. 433-438) and the like. In the present embodiment, the material properties of the unvulcanized rubber are defined based on these documents. Each component model 13 is stored in the computer 1.

  Next, in the green tire model input step S3 of the present embodiment, the member models 13 are bonded to each other (bonding step S32). FIG. 8 is a flow chart for explaining an example of the processing procedure of the bonding step S32.

  In the bonding step S32 of the present embodiment, first, the member models 13a to 13k shown in FIG. 7 are arranged under boundary conditions that allow mutual overlapping (step S41). FIG. 9 is a conceptual view showing an example of a member model 13 having an overlapping portion.

  In step S41, the member models 13a to 13k are arranged such that distances (distances in the radial direction) from the axial center of a forming drum (not shown) for forming the members 3 in an annular shape are aligned. Thus, the first laminate model 25, the second laminate model 26, and the tread ring model 28 are set.

  The first laminate model 25 is defined by the arrangement of the inner liner rubber model 13e, the carcass ply model 13g, the clinch rubber model 13c, the sidewall rubber model 13b, and the cushion rubber model 13k. The second laminate model 26 is defined by the arrangement of the bead core model 13 f and the bead apex rubber model 13 d. The tread ring model 28 is defined by the arrangement of the tread rubber model 13a, the inner belt ply model 13h, the outer belt ply model 13i, and the covering rubber model 13j.

  In step S41, under the boundary conditions under which mutual overlapping is permitted without changing the cross-sectional shape of each of member models 13a to 13k (that is, without considering the cross-sectional shape after lamination of members 3). The member models 13a to 13k are arranged. For this reason, the plurality of member models 13a to 13k are provided with an overlapping portion 23 (indicated by a broken line in FIG. 9) at least a part of which overlaps each other.

  Next, in the bonding step S32 of the present embodiment, each member model 13a to 13k is deformed so as to eliminate the overlapping portion 23 (step S42). In the step S42, the overlapping portion 23 is eliminated by deforming the member models 13a to 13k inward in the radial direction or outward in the radial direction. FIG. 10 is a conceptual view showing an example of a member model 13 after deformation.

  About the deformation | transformation method of each member model 13a-13k, it can employ | adopt suitably. In step S42 of the present embodiment, the member models 13a to 13k are deformed (expanded or contracted) based on the thermal expansion coefficients of the member models 13a to 13k and the temperatures set for the member models 13a to 13k. The temperature is set to a value different from the initial temperature (for example, the temperature at the time of manufacturing the green tire 2) set in the member models 13a to 13k. Thereby, in process S42, member model 13a-13k can be expanded or contracted by temperature difference with initial temperature, and duplication of each member model 13a-13k can be eliminated.

  The deformation calculation of the member models 13a to 13k is based on the shape of each element H (i), the thermal expansion coefficient, and the material characteristics shown in FIG. 1, ...)). Such deformation calculation can be calculated, for example, using a commercially available finite element analysis application software such as LS-DYNA manufactured by JSOL.

  Next, in the bonding step S32 of the present embodiment, the member models 13a to 13k are brought into close contact (step S43). In step S43, the member models 13a to 13k are in close contact with each other under boundary conditions in which mutual contact is permitted and mutual overlapping is prohibited. FIG. 11 is a conceptual view showing an example of the member model 13 in close contact.

  In step S43, the temperature of the member model 13 set to a temperature different from the initial temperature is changed so as to gradually approach the initial temperature. Thereby, in step S43, the first laminate model 25, the second laminate model 26, and the tread ring model 28 in which at least a part of the member models 13a to 13k adjacent in the radial direction are in close contact with each other are set. Can.

  Next, in the bonding step S32 of the present embodiment, a casing model in which the first laminate model 25 and the second laminate model 26 are in close contact is set (step S44), and the casing model bulges outward in the radial direction. The deformation calculation to be performed is performed (step S45). FIG. 12 is a conceptual view showing an example of a casing model 27 bulging outward in the radial direction.

  In step S45, the bead portions 27c, 27c are moved inward in the tire axial direction so as to reduce the axial distance of the bead portions 27c, 27c of the casing model 27 in the tire axial direction, and the casing model 27 bulges radially outward. Calculation of deformation is performed. The bulging of the casing model 27 is calculated based on the equally distributed load w1 defined on the inner surface of the casing model 27. The equal distribution load w1 is set based on the pressure of high pressure air that causes the casing (not shown) of the green tire 2 shown in FIG. 2 to bulge. The bulging of the casing model 27 allows the outer surface of the casing model 27 to be in contact with the inner surface of the tread ring model 28.

  Next, in the bonding step S32 of the present embodiment, the tread ring model 28 is deformed toward the casing model 27 (step S46). FIG. 13 is a conceptual view showing an example of the deformed tread ring model 28. As shown in FIG. The deformation of the tread ring model 28 is calculated based on the equally distributed load w2 defined on the outer surface of the tread ring model 28. The equally distributed load w2 is set based on the pressure of a stitching roller (not shown) pressing the outer peripheral surface of the tread ring (not shown) of the green tire 2 shown in FIG. Thereby, in step S46, deformation calculation of the tread ring model 28 can be performed such that the inner surface of the tread ring model 28 follows the outer surface of the casing model 27.

  Next, in the bonding step S32 of the present embodiment, the protruding portion 27p of the casing model 27 protruding outside in the tire axial direction with respect to the bead core model 13f is rolled up around the bead core model 13f (step S47). In step S47, the protruding portion 27p is rolled up based on the equally distributed load w3 defined on the inner surface of the protruding portion 27p of the casing model 27. The equally distributed load w3 is set based on the pressure of a bladder (not shown) pressing the inner surface of the protruding portion (not shown) of the green tire 2 shown in FIG.

  In step S47, deformation calculation of the rolled up protruding portion 27p and the bead apex rubber model 13d is performed such that the outer surface of the protruding portion 27p is in close contact with the outer surface of the carcass ply model 13g or the outer surface of the tread rubber model 13a. . Thereby, in joining process S32, each member model 13a-13k can be stuck mutually without a clearance gap. FIG. 14 is a conceptual view showing an example of a green tire model 12.

  Next, in the bonding step S32 of the present embodiment, the close contact state is maintained so that the member models 13a to 13k are not separated from each other (step S48). In step S48, boundary conditions that prevent relative movement are set on the contact surfaces between the member models 13 and 13 in close contact with each other. Thus, the raw tire model 12 is defined.

  As described above, in the green tire model input step S3 of the present embodiment, the member models 13a to 13k can be stacked and brought into close contact with each other as in the actual manufacturing method of the green tire 2. Therefore, in the raw tire model input step S3 of the present embodiment, it is possible to create a raw tire model 12 that accurately reproduces the shape of the actual raw tire 2 (shown in FIG. 2). The raw tire model 12 is stored in the computer 1.

  Next, according to the vulcanization simulation method of the present embodiment, the computer 1 generates a green tire model 12 in the cavity 24 of the mold model 16 in a state where the first mold piece model 17 and the second mold piece model 18 are open. Are placed (step S4). FIG. 15 is a conceptual view showing an example of the raw tire model 12 disposed in the cavity 24 of the mold model 16. In FIG. 15, the mold model 16 and the bladder model 20 are colored.

  In step S4, first, the first mold piece model 17 and the second mold piece model 18 are disassembled to move the first mold piece model 17 radially outward, and the second mold piece model 18 Move axially outward. Thereby, it is possible to define the mold model 16 in a state in which the first mold piece model 17 and the second mold piece model 18 are open.

  The first mold piece model 17 is located more radially outward than the green tire model 12. On the other hand, the second mold piece model 18 is located on the outer side in the tire axial direction than the green tire model 12. As a result, the green tire model 12 is disposed in the mold model 16 in a state where the first mold piece model 17 and the second mold piece model 18 are open.

  Next, in the vulcanization simulation method of the present embodiment, the computer 1 arranges the bladder model 20 in the lumen of the green tire model 12 (step S5). In step S5 of the present embodiment, the bladder model 20 is disposed in the lumen of the green tire model 12 so as not to contact the green tire model 12 and the mold model 16.

  Next, in the vulcanization simulation method of the present embodiment, the computer 1 closes the mold model 16 so that the first mold piece model 17 and the second mold piece model 18 gradually approach each other ( Mold closing step S6). FIG. 16 is a flowchart showing an example of the processing procedure of the mold closing step S6.

  In the mold closing step S6 of the present embodiment, the raw tire model 12, the first mold piece model 17, the second mold piece model 18, and the bladder model 20 shown in FIG. Boundary conditions which are permitted and whose mutual overlap is prohibited are defined (step S61). Boundary conditions are stored in the computer 1.

  Next, in the mold closing step S6 of the present embodiment, the bladder model 20 is expanded and deformed (step S62). In step S62, an equally distributed load w4 is defined on the inner surface 20i of the bladder model 20. The equally distributed load w4 corresponds to the pressure of the high pressure air that causes the bladder 10 shown in FIG. 3 to bulge. Thereby, in step S62, it is possible to carry out deformation calculation for causing the bladder model 20 to bulge outward in the radial direction. The green tire model 12 can be pressed toward the first mold piece model 17 and the second mold piece model 18 by the bulging deformation of the bladder model 20.

  Next, in the mold closing step S6 of the present embodiment, the first mold piece model 17 and the second mold piece model 18 are gradually approached (step S63). In step S63, the first mold piece model 17 and the second mold piece model 18 are made to approach at every unit time of simulation at a predetermined speed. Thus, in the mold closing step S6, it is possible to calculate the state in which the mold model 16 is closed so that the first mold piece model 17 and the second mold piece model 18 gradually approach. FIG. 17 is a conceptual diagram for explaining a state in which the first mold piece model 17 and the second mold piece model 18 are closed. In FIG. 17, the mold model 16 and the bladder model 20 are colored. FIG. 18 is a conceptual diagram illustrating a state in which a part of the green tire model 12 is sandwiched between the first mold piece model 17 and the second mold piece model 18.

  Next, in the mold closing step S6 of the present embodiment, in the process of the computer 1 closing the mold model 16, a green tire is formed between the first mold piece model 17 and the second mold piece model 18. It is determined whether a part of the model 12 is pinched (step S64). In step S64, the element H (i) of the green tire model 12 shown in FIG. 18 abuts on the mating surface 31 of the first mold piece model 17 or the mating surface 32 of the second mold piece model 18 ( For example, it is performed by checking whether or not surface contact is made.

  In step S64, a part of the raw tire model 12 is sandwiched between the first mold piece model 17 and the second mold piece model 18 (ie, the element H (i) of the raw tire model 12 is joined). When it is determined that the surface 31 or 32 abuts ("Y" in step S64), rubber biting occurs in the mold 6 (shown in FIG. 3) manufactured based on the mold model 16 It can be predicted. In this case, the mold 6 is redesigned (step S65) so that rubber biting does not occur, and the mold 6 is manufactured (step S66). Thereby, in the vulcanization simulation method of the present embodiment, the mold 6 in which rubber biting does not occur can be designed and manufactured. The vulcanization simulation method of the present embodiment may be implemented again based on the mold 6 whose design has been changed. In the present embodiment, when it is determined in step S64 that the element H (i) of the green tire model 12 abuts on the mating surface 31 or 32, the first mold piece model 17 and the second mold piece model Approach with 18 is interrupted.

  On the other hand, when it is determined in step S64 that a part of the green tire model 12 is not sandwiched between the first mold piece model 17 and the second mold piece model 18 (“N” in step S64) And the computer 1 determines whether the mold model 16 is closed (step S67). Whether or not the mold model 16 is closed is determined by whether or not the mating surface 31 of the first mold piece model 17 abuts on the mating surface 32 of the second mold piece model 18.

  If it is determined in step S67 that the mold model 16 is closed ("Y" in step S67), the mold model 16 can be closed without rubber biting. In this case, in the mold 6 (shown in FIG. 3) manufactured based on the mold model 16, it can be predicted that rubber biting will not occur. Therefore, the mold 6 is manufactured based on the mold model 16 (step S66).

  On the other hand, if it is determined in step S67 that the mold model 16 is not closed ("Y" in step S67), the unit time is advanced by 1 (step S68) and steps S63 and S64 are performed again. Be done. Thereby, in the mold closing step S6, a part of the green tire model 12 is pinched between the first mold piece model 17 and the second mold piece model 18 until the mold model 16 is closed. It can be determined whether or not

  Thus, according to the vulcanization simulation method of the present embodiment, a part of the green tire 2 is formed between the first mold piece 7 and the second mold piece 8 before actually manufacturing the mold 6. The presence or absence of so-called rubber bite to be pinched can be determined using the computer 1. Therefore, the vulcanization simulation method of the present embodiment helps to design and manufacture the mold 6 capable of preventing rubber biting without requiring much time and cost.

  Further, in step S64 of this embodiment, the element H (i) of the green tire model 12 abuts on the mating surface 31 of the first mold piece model 17 or the mating surface 32 of the second mold piece model 18 If so, the approach between the first mold piece model 17 and the second mold piece model 18 is interrupted. Thus, in the vulcanization simulation method of the present embodiment, the element H (i) of the green tire model 12 is the mating surface 31 of the first mold piece model 17 or the mating surface 32 of the second mold piece model 18. The first mold piece model 17 and the second mold piece model 18 can be prevented from approaching each other to cause element crushing even after contact with Therefore, since the vulcanization simulation method of the present embodiment can prevent calculation omission due to element crushing, the presence or absence of rubber biting can be stably determined.

  Furthermore, in the vulcanization simulation method of the present embodiment, since the green tire model 12 with high accuracy in which the member models 13 are joined to each other is used, the presence or absence of rubber biting can be determined with high accuracy. Therefore, the vulcanization simulation method of the present embodiment helps to design and manufacture the mold 6 capable of more reliably preventing the rubber bite.

  In the vulcanization simulation method of the present embodiment, the green tire model 12 in which the member models are joined to each other is defined, but the present invention is not limited to such an aspect. For example, based on the cross-sectional shape of the mold 6, a raw tire model (not shown) discretized with a finite number of elements H (i) may be defined. Such a raw tire model 12 helps to reduce the calculation time.

  As mentioned above, although the especially preferable embodiment of this invention was explained in full detail, this invention can be deform | transformed into a various aspect, and can be implemented, without being limited to embodiment of illustration.

  Based on the processing procedure shown in FIG. 4, it includes at least a first mold piece and a second mold piece arranged to be openable / closable, and by closing, the first mold piece and the second mold piece Using a computer, it was simulated that a green tire (size: 295 / 75R22.5) was vulcanized and formed with a mold (shown in FIG. 3) that forms a cavity partitioned by a molding surface across the Example).

  In the embodiment, the green tire model is placed in the cavity of the mold model in a state where the first mold piece model and the second mold piece model are open, and the first gold is prepared based on the processing procedure shown in FIG. In the process of closing the mold model so that the mold piece model and the second mold piece model gradually approach each other, between the first mold piece model and the second mold piece model, It was judged whether part was caught or not.

  In the example, as shown in FIG. 18, it was possible to determine so-called rubber bite in which a part of the green tire model is sandwiched between the first mold piece model and the second mold piece model. .

  Based on the results of the rubber bite, in the example, a design change of the mold was made. Then, based on the modified mold, it was determined whether or not a part of the green tire model was caught between the first mold piece model and the second mold piece model. FIG. 19 is a conceptual view showing a process of closing a design-changed mold model.

  In the modified mold, a part of the green tire model was not sandwiched between the first mold piece model and the second mold piece model. And although a redesigned mold was actually manufactured, no rubber bite of the green tire occurred. Therefore, in the example, it was possible to design and manufacture a mold 6 capable of preventing rubber biting.

S1 A step of inputting a mold model S3 A step of inputting a raw tire model S4 A step of arranging a raw tire model in a cavity of a mold model S6 A step of judging whether a part of the raw tire model is caught

Claims (5)

A cavity defined by a molding surface including at least a first mold piece and a second mold piece arranged to be openable and closable, and being closed and spanning the first mold piece and the second mold piece Using a computer to simulate how a green tire is vulcanized and formed with a mold that forms
Inputting a mold model including a first mold piece model and a second mold piece model obtained by discretizing the first mold piece and the second mold piece with a finite number of elements into the computer; ,
Inputting a raw tire model obtained by discretizing the raw tire with a finite number of elements into the computer;
Placing the green tire model in the cavity of the mold model with the first mold piece model and the second mold piece model open;
Closing the mold model so that the computer gradually approaches the first mold piece model and the second mold piece model;
In the process of closing the mold model, the computer determines whether or not a part of the green tire model is caught between the first mold piece model and the second mold piece model. Including the steps of
A method of simulating the vulcanization of a green tire. The first mold piece model and the second mold piece model have mating surfaces that contact each other when the mold model is closed,
The method of simulating the vulcanization of a green tire according to claim 1, wherein the step of judging is performed by checking whether the element of the green tire model is in contact with the mating surface.   In the step of closing the mold model, when it is determined that the element of the green tire model is in contact with the mating surface, the first mold piece model and the second mold piece model The method of simulating vulcanization of a green tire according to claim 2, wherein the approach is interrupted. The green tire includes a plurality of members joined together,
4. The method according to claim 1, wherein the step of inputting the green tire model includes a step of joining the member models obtained by discretizing the members with a finite number of elements to define the green tire model. 5. Simulation method of green tire vulcanization. The method further includes the step of inputting a bladder model discretized with a finite number of elements by pressing the green tire to the mold side by the expansion in the inner cavity of the green tire.
The step of closing the mold includes a step of pressing the green tire model toward the first mold piece model and the second mold piece model by expansion deformation of the bladder model. The vulcanization | cure simulation method of the green tire in any one of 4.