JP6592338B2 - Method, apparatus and program for determining durability of tire vulcanizing mold - Google Patents

Description

  The present disclosure relates to a tire vulcanization mold durability determination method, apparatus, and program.

  A mold for vulcanizing a pneumatic tire includes a first side mold and a second side mold which are arranged on both sides in the tire axial direction to form a side wall, and a plurality of sectors arranged in an annular shape. A tread mold for forming the tread. The vulcanization of the tire is performed in a closed state in which the butt surface of each side mold and the butt surface of the tread mold are butted against each other. The following patent document 1 is mentioned as a related technique.

JP 2013-95096 A

  By the way, a large contact pressure acts on the abutting surface in the side mold and the tread mold due to the load for closing the mold, the expansion due to heat, and the internal pressure received through the tire. Therefore, the abutting surface is easily worn or deformed, and improvement in durability is required. In general, the side mold is often formed of a hard steel material. On the other hand, the tread mold (sector) is often formed of a soft aluminum alloy, and the tread mold is more easily worn or deformed than the side mold.

  In designing a tire vulcanization mold, it is possible to evaluate the durability by manufacturing the actual product and repeatedly vulcanizing the tire and measuring the wear and deformation. However, since this evaluation method requires cost and time, it is considered preferable to perform evaluation by simulation using a computer.

  However, it seems that the technique on how to evaluate the durability of the mold using computer simulation is not disclosed in the literature as the prior art.

  This indication was made paying attention to such a subject, and the object is to provide the method, apparatus, and program which evaluate the endurance of a tire vulcanization metallic mold by computer simulation.

  In order to achieve the above object, the present disclosure takes the following measures.

That is, the method for determining the durability of the tire vulcanization mold according to the present disclosure is as follows.
Setting a mold finite element model having a pair of first and second side molds forming a tire sidewall and a tread mold forming a tire tread;
The tread mold is abutted against the first and second side molds, boundary conditions that allow the abutting surfaces to contact each other are set, the load for closing the mold, the thermal load on the model, and the mold Performing an vulcanization simulation by applying an internal pressure to the molding surface of
Based on the result of the vulcanization simulation, the evaluation corresponding to the difference between the pressure of the surface in contact with the first side mold and the pressure of the surface in contact with the second side mold among the butted surfaces of the tread mold. Calculating a value;
When the evaluation value is outside a predetermined allowable range, it is determined that the durability is poor, and when the evaluation value is within the predetermined allowable range, it is determined that the durability is not defective.
including.

The durability determination device for a tire vulcanization mold according to the present disclosure includes:
A setting unit for setting a mold finite element model having a pair of first and second side molds for forming a sidewall of the tire and a tread mold for forming a tread of the tire;
The tread mold is abutted against the first and second side molds, boundary conditions that allow the abutting surfaces to contact each other are set, the load for closing the mold, the thermal load on the model, and the mold A vulcanization simulation execution unit for executing an vulcanization simulation by applying an internal pressure to the molding surface of
Based on the result of the vulcanization simulation, the evaluation corresponding to the difference between the pressure of the surface in contact with the first side mold and the pressure of the surface in contact with the second side mold among the butted surfaces of the tread mold. An evaluation value calculation unit for calculating a value;
When the evaluation value is outside the predetermined allowable range, it is determined that the durability is poor, and when the evaluation value is within the predetermined allowable range, the determination unit determines that the durability is not defective,
Is provided.

  Thus, the evaluation value corresponding to the difference between the pressure of the surface that contacts the first side mold and the pressure of the surface that contacts the second side mold among the butt surfaces of the tread mold is calculated. Therefore, when the stress difference is large and the evaluation value is outside the predetermined allowable range, it is determined that the durability is poor, and when the stress difference is small and the evaluation value is within the predetermined allowable range, it is determined that the durability is not defective. The durability of the mold can be evaluated based on the stress difference without performing a test with an actual machine, and the cost and time can be reduced.

The perspective view which shows the structure of the tire vulcanization metal mold | die used as analysis object in this indication. Sectional drawing which shows a tire vulcanization metal mold | die. The block diagram which shows the determination apparatus which concerns on this indication. The perspective view which shows a tire vulcanization die finite element model. The figure which shows a simulation result. 7 is a flowchart illustrating a durability determination processing routine executed by a determination device according to the present disclosure.

  Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[Tire vulcanization mold]
As shown in FIGS. 1 and 2, the tire vulcanization mold M to be simulated has a tread mold 2 for molding a tire tread. The tread mold 2 is a plurality of sectors 2 divided in the tire circumferential direction, and a tread molding surface continuous in an annular shape is formed by combining the division surfaces 2 a of the sectors 2.

  The tire vulcanization mold M is used so that the rotation axis of the unvulcanized tire is vertical, and a pair of first side mold 3a (upper side plate 3a) and second side forming a sidewall of the tire are formed. A side mold 3b (lower side plate 3b) is provided. The tire vulcanization mold M includes a segment 4 that is fixed to the outer side in the tire radial direction of the tread mold 2 and has an inclined surface 4a, and an inclined surface 5a that faces the inclined surface 4a of the segment 4, and the segment 4 and the tread mold are moved downward. Jacket ring 5 that presses 2 inward in the tire radial direction and clamps, lower seal plate 6a disposed below the second side mold 3b, and upper dummy disposed above the first side mold 3a A plate 6b and an upper seal plate 6c. A metal plate 7a is disposed between the segment 4 and the jacket ring 5, and a lower plate 7b is disposed between the segment 4 and the lower seal plate 6a.

  The tire vulcanization mold M expands the diameter of the tread mold 2 by separating the split surfaces 2a by positioning the jacket ring 5 upward. After throwing in the raw tire (not shown), the first side mold 3a and the jacket ring 5 are lowered to bring the divided surface 2a of the tread mold 2 close to each other, and the raw tire is vulcanized.

[Judgment device]
The determination device evaluates the durability of the tire vulcanization mold using the mold finite element model data in which the tire vulcanization mold M is represented by a finite element.

  Specifically, as shown in FIG. 3, the apparatus 1 includes a setting unit 10, a vulcanization simulation execution unit 11, a pressure calculation unit 12, an evaluation value calculation unit 13, and a determination unit 14. These units 10 to 14 are realized by cooperation of software and hardware by executing a processing routine (not shown) stored in advance by the CPU in an information processing apparatus such as a personal computer having a CPU, memory, various interfaces, and the like. Is done.

  The setting unit 10 shown in FIG. 3 accepts an operation from a user via a known operation unit such as a keyboard and a mouse, and sets the mold finite element model M to be analyzed and analysis conditions used in the vulcanization analysis. Execute and store these set values in the memory.

  The mold finite element model M includes first and second side molds (3a, 3b) forming a pair for forming a sidewall of the tire, and a tread mold 2 for forming a tire tread. Each member constituting the metal mold M is configured by a finite number of elements (see FIG. 4). Nodes are defined at element boundaries, and equations of motion are calculated for each node. For each element, for example, node coordinate values, element shapes, material characteristics, and the like are defined. In this embodiment, as shown in FIGS. 1 and 2, the mold finite element model M has a sector shape with a central angle of 40 °, and both end faces in the circumferential direction are the centers of the tread mold 2. In the present embodiment, nine divisions are performed at a central angle of 40 °, but the present invention is not limited to this.

  The longitudinal elastic modulus of the tread mold 2 is set to be lower than that of the first and second side molds 3a and 3b. For this reason, the tread mold 2 is easily worn out with respect to the side molds 3a and 3b.

  The analysis conditions are the vertical load for closing the mold (A in FIGS. 1 and 3), the thermal load applied to the mold finite element model M (from room temperature to vulcanization temperature; B in FIG. 3), and the molding surface of the mold The internal pressure (C in FIG. 1 and FIG. 3) that acts on Further, as an option, the clearance between the tread molds 2 (D in FIGS. 1 and 3), the preload (E in FIGS. 1 and 3) that is the gap between the upper dummy plate 6b and the upper seal plate 6c, and the axial direction of the bolt It is possible to set the fastening force (F in FIGS. 1 and 3) of the bolt acting along the line.

  As the contact condition and the bonding condition, as shown in FIG. 2, boundary conditions that allow contact with the butted surfaces of the tread mold 2 with respect to the first side mold 3 a and the second side mold 3 b are set. In addition, contact conditions and coupling conditions are defined for each member. In FIG. 2, the contact definition is indicated by a circle, and the coupling constraint is indicated by x.

  The vulcanization simulation execution unit 11 shown in FIG. 3 sets a boundary condition that allows the tread mold 2 to abut against the first and second side molds (3a, 3b) and enables the abutting surfaces to contact each other. Then, a vulcanization simulation is executed by applying an internal pressure to the load for closing the mold, the thermal load on the model, and the molding surface of the mold. As a calculation procedure, first, a bolt load is applied between the tread mold 2 and the segment 4, then, an expansion calculation is performed by applying a thermal load to the entire mold finite element model M, and then the mold is mounted. A vertical load is applied for clamping, and the mold is clamped by the preload set between the upper dummy plate 6b and the upper seal plate 6c. Next, the first side mold 3a, the second side mold 3b, and the segment 4 are clamped. Internal pressure is applied to each molding surface. In this state, the behavior of each member is simulated. Note that a tire model is not used for easy calculation.

  The pressure calculation unit 12 illustrated in FIG. 3 calculates the contact pressure generated on the butted surfaces 2c and 2d of the tread mold 2 based on the result of the vulcanization simulation by the vulcanization simulation executing unit 11. The pressure value is calculated for each element as shown in FIG.

  The evaluation value calculation unit 13 illustrated in FIG. 3 includes a pressure of a surface 2c (hereinafter, simply referred to as “upper surface”) that contacts the first side mold 3a among the butted surfaces of the tread mold 2, and a second An evaluation value corresponding to the difference in pressure of the surface 2d (hereinafter sometimes simply referred to as “lower surface”) in contact with the side mold 3b is calculated. In the present embodiment, the contact pressure ratio (lower surface / upper surface) is calculated as the evaluation value, but the present invention is not limited to this. The ratio may be (upper surface / lower surface), for example, a pressure difference.

  In the present embodiment, as illustrated in FIG. 5, the surface (upper surface 2 c) that contacts the first side mold 3 a and the surface (lower surface 2 d) that contacts the second side mold 3 b are arranged in the tire circumferential direction. It has a column composed of a plurality of arranged elements. A plurality of rows are arranged along the tire axial direction, and are arranged in a matrix. The elements on the surface (upper surface 2c) in contact with the first side mold 3a and the elements on the surface (lower surface 2d) in contact with the second side mold 3b are symmetric with respect to the tire equator. Of course, the shape and arrangement of the elements are not limited to this. As illustrated in FIG. 5, the evaluation value calculation unit 13 calculates an evaluation value corresponding to a pressure difference between columns that are symmetrical to each other. Specifically, the ratio between the first row of the upper surface 2c and the first row of the lower surface 2d, the ratio of the second row of the upper surface 2c and the second row of the lower surface 2d, 3 of the third row of the upper surface 2c and the lower surface 2d. The values of corresponding columns are used as the ratio to the column.

  Furthermore, the evaluation value calculation unit 13 calculates an evaluation value corresponding to the pressure difference between the parts that are symmetrical to each other and that have the same circumferential position. Specifically, as shown in FIG. 5, the pressure ratio of the end face of the first row (distance 0 mm from the end face) can be calculated. Similarly, the calculation is performed by changing the row and the circumferential position. FIG. 5 is a result of calculating from the end surface of the tread mold 2 to the center for each element for the first to third rows. The evaluation value calculation method is not limited to the above. For example, as an evaluation value method corresponding to the pressure difference between rows that are symmetrical to each other, in addition to the above, the average value of pressure values in the first row on the upper surface 2c and the average value of pressure values in the first row on the lower surface 2d A ratio with the value may be taken. Furthermore, a ratio between the average value of the pressure values of the entire upper surface 2c and the average value of the pressure values of the entire lower surface 2d may be taken.

  The determination unit 14 illustrated in FIG. 3 determines that the durability is poor when the evaluation value is outside the predetermined allowable range, and determines that the durability is not the defective durability when the evaluation value is within the predetermined allowable range. In the example of FIG. 5, if all the evaluation values (ratio) are 0.7 or more and 1.3 or less, it may be set within a predetermined allowable range. That is, if the evaluation value exceeds the direction in which the pressure difference becomes larger than a predetermined threshold, the determination unit 14 determines that the durability is poor. On the other hand, when the evaluation value exists in a direction in which the pressure difference becomes smaller than the threshold value, the determination unit 14 determines that the durability is not defective.

[Evaluation methods]
The operation of the apparatus 1 will be described with reference to FIG.

  First, in step ST1, the setting unit 10 shown in FIG. 3 accepts an operation from a user via a known operation unit such as a keyboard or a mouse, and is used in a mold finite element model M to be analyzed and vulcanization analysis. Set the analysis conditions to be performed. As a result, the setting unit 10 has a mold finite element model M having the first and second side molds 3a and 3b that form a pair for forming the sidewall of the tire, and the tread mold 2 for forming the tire tread. Will be set.

  In the next step ST2, the vulcanization simulation executing unit 11 sets the boundary condition that allows the tread mold 2 to abut against the first and second side molds 3a and 3b and enables the abutting surfaces to contact each other. Then, a vulcanization simulation is executed by applying an internal pressure to the load for closing the mold, the thermal load on the model, and the molding surface of the mold.

  In the next step ST3, the pressure calculation unit 12 calculates the contact pressure generated on the butted surfaces 2c and 2d of the tread mold 2 based on the result of the vulcanization simulation. In the next step ST4, the evaluation value calculation unit 13 determines the difference between the pressure on the surface (upper surface 2c) in contact with the first side mold 3a and the pressure on the surface (lower surface 2d) in contact with the second side mold 3b. The corresponding evaluation value is calculated.

  In the next step ST5, when the evaluation value is outside the predetermined allowable range (ST5: YES), the determination unit 14 determines that the durability is poor (ST6). In step ST5, when the evaluation value is within the predetermined allowable range (ST5: NO), the determination unit 14 determines that the durability is not defective (ST7).

  If it is determined that the durability is poor, the following two design changes can be considered.

(1) Size and arrangement change of the metal plate 7a By changing the contact position of the metal plate 7a with respect to the segment 4 and the jacket ring 5, the force sharing to the upper surface 2c and the lower surface 2d of the tread mold 2 is changed. For example, when pressure is applied to the upper surface 2c rather than the lower surface 2d, the lower surface 2d is tightened if the metal plate 7a is moved downward.

(2) Shape change of jacket ring 5 The thickness in the tire radial direction is increased on the side where the contact pressure is low. When the contact pressure of the lower surface 2d is smaller than the upper surface 2c, the thickness below the jacket ring 5 can be increased.

As described above, the method for determining the durability of the tire vulcanization mold according to the present embodiment is as follows.
A step (ST1) of setting a mold finite element model M having a pair of first and second side molds 3a and 3b forming a tire sidewall and a tread mold 2 for molding a tire tread; ,
Loads for closing the mold, setting the boundary condition that enables the tread molds 2 to be in contact with the first and second side molds 3a and 3b, allowing the contact surfaces to contact each other, and thermal load on the model And a step of performing an vulcanization simulation by applying an internal pressure to the molding surface of the mold (ST2),
Based on the result of the vulcanization simulation, the difference between the pressure of the surface 2c in contact with the first side mold 3a and the pressure of the surface 2d in contact with the second side mold 3b out of the butted surfaces 2c and 2d of the tread mold 2 A step of calculating an evaluation value corresponding to (ST3-4),
When the evaluation value is outside the predetermined allowable range, it is determined that the durability is poor, and when the evaluation value is within the predetermined allowable range, it is determined that the durability is not defective (ST5 to 7);
including.

The tire vulcanization mold durability determination device of the present embodiment is
A setting unit 10 for setting a mold finite element model M having a pair of first and second side molds 3a and 3b forming a tire sidewall and a tread mold 2 for molding a tire tread;
Loads for closing the mold, setting the boundary condition that enables the tread molds 2 to be in contact with the first and second side molds 3a and 3b, allowing the contact surfaces to contact each other, and thermal load on the model And a vulcanization simulation executing unit 11 that executes an vulcanization simulation by applying an internal pressure to the molding surface of the mold,
Based on the result of the vulcanization simulation, the difference between the pressure of the surface 2c in contact with the first side mold 3a and the pressure of the surface 2d in contact with the second side mold 3b among the butted surfaces 2c and 2d of the tread mold. An evaluation value calculation unit 13 for calculating a corresponding evaluation value;
When the evaluation value is outside the predetermined allowable range, it is determined that the durability is poor, and when the evaluation value is within the predetermined allowable range, the determination unit 14 determines that the durability is not defective,
Is provided.

  The predetermined allowable range is a range in which the pressure difference is small and the durability is not poor.

  According to this structure, it corresponds to the difference between the pressure of the surface 2c in contact with the first side mold 3a and the pressure of the surface 2d in contact with the second side mold 3b out of the butted surfaces 2c and 2d of the tread mold 2. The evaluation value is calculated, and based on this evaluation value, when the stress difference is large and the evaluation value is outside the predetermined allowable range, it is determined that the durability is poor. When the stress difference is small and the evaluation value is within the predetermined allowable range, Since it is determined that the durability is not poor, the durability of the mold can be evaluated based on the stress difference without performing a test with an actual machine, and the cost and time can be reduced.

In this embodiment, the surface 2c in contact with the first side mold 3a and the surface 2d in contact with the second side mold 3b have a row composed of a plurality of elements arranged in the tire circumferential direction. Are lined up along the tire axial direction,
The element on the surface 2c in contact with the first side mold 3a and the element on the surface 2d in contact with the second side mold 3b are symmetric with respect to the tire equator.
In the method of this embodiment, the step ST4 of calculating the evaluation value calculates an evaluation value corresponding to the pressure difference between the rows that are symmetrical to each other.
In the apparatus of the present embodiment, the evaluation value calculation unit 13 calculates an evaluation value corresponding to a pressure difference between columns that are symmetrical to each other.

  According to this configuration, since the evaluation value corresponding to the pressure difference is calculated in consideration of the distribution of the pressure in the tire axial direction, the determination accuracy can be improved.

In the method of the present embodiment, the step ST4 for calculating the evaluation value calculates an evaluation value corresponding to the pressure difference between the parts that are symmetrical to each other and that have the same circumferential position.
In the apparatus according to the present embodiment, the evaluation value calculation unit 13 calculates an evaluation value corresponding to a pressure difference between parts that are in a symmetrical relationship with each other and that have the same circumferential position.

  According to this configuration, since the evaluation value corresponding to the pressure difference is calculated in consideration of not only the tire axial distribution but also the circumferential distribution, it is possible to improve the determination accuracy.

The program according to the present embodiment causes a computer to execute each step constituting the method.
By executing these programs, it is possible to obtain the operational effects of the above method. In other words, it can be said that the above method is used.

  As mentioned above, although embodiment of this indication was described based on drawing, it should be thought that a specific structure is not limited to these embodiment. The scope of the present disclosure is indicated not only by the above description of the embodiments but also by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, each of the units 10 to 14 illustrated in FIG. 3 is realized by executing a predetermined program by a CPU of a computer, but each unit may be configured by a dedicated memory or a dedicated circuit.

In this embodiment, the mold uses a sector, but a two-piece mold may be used.

  The structure employed in each of the above embodiments can be employed in any other embodiment. The specific configuration of each unit is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present disclosure.

DESCRIPTION OF SYMBOLS 10 ... Setting part 11 ... Vulcanization simulation execution part 13 ... Evaluation value calculation part 14 ... Determination part 3a ... 1st side mold 3b ... 2nd side mold 2 ... Tread mold 2c ... Butt surface (upper surface)
2d ... Butting surface (bottom surface)

Claims (7)

Setting a mold finite element model having a pair of first and second side molds forming a tire sidewall and a tread mold forming a tire tread;
The tread mold is abutted against the first and second side molds, boundary conditions that allow the abutting surfaces to contact each other are set, the load for closing the mold, the thermal load on the model, and the mold Performing an vulcanization simulation by applying an internal pressure to the molding surface of
Based on the result of the vulcanization simulation, the evaluation corresponding to the difference between the pressure of the surface in contact with the first side mold and the pressure of the surface in contact with the second side mold among the butted surfaces of the tread mold. Calculating a value;
When the evaluation value is outside a predetermined allowable range, it is determined that the durability is poor, and when the evaluation value is within the predetermined allowable range, it is determined that the durability is not defective.
For determining durability of tire vulcanizing mold including The surface in contact with the first side mold and the surface in contact with the second side mold have a row composed of a plurality of elements arranged in the tire circumferential direction, and the row is along the tire axial direction. Are lined up,
The element on the surface in contact with the first side mold and the element on the surface in contact with the second side mold are symmetric with respect to the tire equator,
The method according to claim 1, wherein the step of calculating the evaluation value calculates an evaluation value corresponding to a pressure difference between columns that are symmetrical to each other.   The method according to claim 2, wherein the step of calculating the evaluation value calculates an evaluation value corresponding to a pressure difference between parts that are symmetrical to each other and that have the same circumferential position. A setting unit for setting a mold finite element model having a pair of first and second side molds for forming a sidewall of the tire and a tread mold for forming a tread of the tire;
The tread mold is abutted against the first and second side molds, boundary conditions that allow the abutting surfaces to contact each other are set, the load for closing the mold, the thermal load on the model, and the mold A vulcanization simulation execution unit for executing an vulcanization simulation by applying an internal pressure to the molding surface of
Based on the result of the vulcanization simulation, the evaluation corresponding to the difference between the pressure of the surface in contact with the first side mold and the pressure of the surface in contact with the second side mold among the butted surfaces of the tread mold. An evaluation value calculation unit for calculating a value;
When the evaluation value is outside the predetermined allowable range, it is determined that the durability is poor, and when the evaluation value is within the predetermined allowable range, the determination unit determines that the durability is not defective,
An apparatus for determining the durability of a tire vulcanization mold comprising: The surface in contact with the first side mold and the surface in contact with the second side mold have a row composed of a plurality of elements arranged in the tire circumferential direction, and the row is along the tire axial direction. Are lined up,
The element on the surface in contact with the first side mold and the element on the surface in contact with the second side mold are symmetric with respect to the tire equator,
The apparatus according to claim 4, wherein the evaluation value calculation unit calculates an evaluation value corresponding to a pressure difference between columns that are symmetrical to each other.   The apparatus according to claim 5, wherein the evaluation value calculation unit calculates an evaluation value corresponding to a pressure difference between parts that are symmetrical to each other and have the same circumferential position.   The program which makes a computer perform the method in any one of Claims 1-3.