JP2019218017A - Tire simulation method and device - Google Patents

Abstract

To provide a time simulation method and device capable of predicting the anti-detachment performance of a stud pin fit into a stud hole with high accuracy.SOLUTION: In a tire model 6 created by setting pull-out directions Pa to Pm of a stud pin model 4, adding a first node 60 set at a position corresponding to a tip of the stud pin 3 and second nodes 70a to 70m set at positions separated from the first node 60 in the pull-out directions Pa to Pm, setting constraint conditions of the first node 60 and the second nodes 70a to 70m such that the second nodes 70a to 70m are moved only in corresponding pull-out directions Pa to Pm while the second nodes 70a to 70m maintain a constant distance to the first node 60, and fitting the stud pin model 4 into a stud hole 2 of a rubber model 5, reaction force generated in the rubber model 5 is acquired by moving the stud pin model 4 in the pull-out directions Pa to Pm to calculate deformation of the rubber model 5.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a tire simulation method and apparatus for simulating a pull-out force of a stud pin fitted in a stud hole provided in a tread portion.

  A pneumatic tire having stud pins driven into a tread surface is generally called a stud tire or a spike tire, and is mainly used for running on an icy road. In the case of stud tires, it is important to increase the stud pin retention so that the running performance on icy and snowy roads can be sufficiently exhibited.

  Thus, conventionally, it has been proposed to predict the stray pin pull-out resistance using a stud pin model and a rubber model in which each of the tread rubber including the stud pin and the stud hole is modeled by a finite number of elements. (For example, see Patent Document 1 below).

JP 2000-238510

  However, despite the fact that pulling forces are applied to the stud pins from various directions other than the tire radial direction during running of the vehicle, Patent Document 1 only considers the case where the stud pins are pulled outward in the tire radial direction. . Moreover, in the tire, grooves and land portions of various shapes are usually formed in the tread portion, and the directions in which the stud pins are easily pulled out differ depending on these shapes. For this reason, in Patent Literature 1, it is difficult to accurately predict the anti-pulling performance of the stud pin.

  Accordingly, it is an object of the present invention to provide a tire simulation method and apparatus that can accurately predict the anti-pulling performance of a stud pin fitted into a stud hole.

  The present invention provides a method for simulating a tire for simulating a pull-out force of a stud pin fitted in a stud hole provided in a tread portion, wherein a stud pin model obtained by modeling the stud pin with a finite number of elements is provided. Acquiring a rubber model in which at least a part of the tread portion including the stud hole is modeled with a finite number of elements, and setting a first node at a position corresponding to a tip end of the stud pin; Rigidly coupling a first node to the stud pin model, setting a direction in which the stud pin model is pulled out, and adding a second node at a position away from the first node in a direction in which the stud pin model is pulled out; The direction in which the second node is pulled out of the stud pin model while maintaining a constant distance from the first node Setting a constraint condition of the first node and the second node so that the second node moves only, and fitting the stud pin model into the stud hole of the rubber model to create a tire model And obtaining the reaction force generated in the rubber model when the stud pin model is pulled out by moving the stud pin model in the pulling direction in the tire model and calculating the deformation of the rubber model. It is.

  According to the present invention, the pull-out direction of the stud pin can be set in an arbitrary direction, so that the anti-pulling performance of the stud pin can be accurately predicted.

Sectional drawing of the stud pin and the stud hole of a tread part. The figure which shows the simulation device of the tire which concerns on one Embodiment of this invention. The figure which shows a stud pin model typically. The figure which shows a rubber model typically. The perspective view showing an example of the 1st rubber model and the 2nd rubber model. The figure which shows a tire model typically. FIG. 2 is a flowchart showing a simulation method executed by the tire simulation device of FIG. 1.

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

  The tire simulation device (hereinafter, also referred to as “device”) 10 of the present embodiment includes a stud hole 2 provided in a tread portion 1 and a stud fitted in the stud hole 2 as shown in FIG. In the pneumatic tire including the pin 3, the pull-out force of the stud pin 3 fitted in the stud hole 2 is calculated.

  The stud pin 3 provided on the pneumatic tire includes a base 3a fitted into the stud hole 2 of the tread portion 1, and a spike 3c protruding outward from the end face 3b of the base 3a in the tire radial direction. The spike portion 3c protrudes outward in the tire radial direction from the tread surface 1a of the tread portion 1, and contacts the road surface when the pneumatic tire rolls to generate a large frictional force.

  As shown in FIG. 2, the device 10 includes a model acquisition unit 11, a node setting unit 12, a tire model creation unit 13, a reaction force acquisition unit 14, and an analysis unit 20. The model acquisition unit 11, the node setting unit 12, the tire model creation unit 13, and the reaction force acquisition unit 14 have a CPU stored in advance in an information processing device such as a personal computer including a CPU, a memory, and various interfaces. By executing a processing routine (not shown), software and hardware are realized in cooperation.

  The device 10 receives an operation from a user via a known operation unit such as a keyboard or a mouse, and receives data regarding the pneumatic tire and a direction in which the stud pin model 4 is pulled out (hereinafter, also referred to as a “pulling direction”) Pa. The setting of data relating to conditions such as .about.Pm is accepted, and these data are stored in the memory.

  The model acquisition unit 11 acquires a stud pin model acquisition unit 15 that acquires a stud pin model 4 in which the stud pin 3 is modeled with a finite number of elements, and a part of the tread unit 1 including the stud hole 2 with a finite number of elements. A rubber model acquisition unit 16 for acquiring the modeled rubber model 5.

  As shown in FIG. 3, the stud pin model 4 is modeled by a finite number of elements 40 that can be handled by the finite element method. In the present embodiment, a quadrilateral element in which the element 40 has four nodes 41 is used. In addition, for example, a triangular element having three nodes, a beam element having two nodes, A three-dimensional continuum element having four or more nodes may be used.

  The spike portion 3c does not affect the fitting of the tread portion 1 with the stud hole 2. Therefore, in the present embodiment, the stud pin model 4 input to the stud pin model acquisition unit 15 is only the base 3a fitted to the stud hole 2 among the base 3a and the spike 3c of the stud pin 3 shown in FIG. Is modeled. Further, the stud pin model 4 of the present embodiment is modeled only in the vicinity of the outer surface of the base 3a of the stud pin 3 (see FIGS. 3 and 6).

  Further, in each element 40, numerical data such as an element number, a number of the node 41, a coordinate value of the node 41, and material characteristics (for example, density, Young's modulus, damping coefficient, etc.) of the stud pin 3 are defined. These numerical data are stored in the memory of the computer.

  As shown in FIGS. 4 and 5, the rubber model 5 input to the rubber model acquisition unit 16 in the present embodiment corresponds to the stud hole 2 and the stud hole 2 obtained by modeling the periphery of the stud hole 2 with a finite number of elements 50a. A first rubber model 5a having holes 7 and a second rubber model 5b obtained by modeling the tread portion 1 with a finite number of elements 50b outside the first rubber model 5a are combined.

  The first rubber model 5a is a model of a cylindrical region provided around the hole 7 corresponding to the stud hole 2.

  The size range of the second rubber model 5b is not particularly limited as long as it is provided outside the first rubber model 5a. For example, as shown in FIG. One block can be modeled, or the entire tread portion 1 can be modeled.

  Like the stud pin model 4, each element 50a, 50b constituting the first rubber model 5a and the second rubber model 5b has an element number, a number of the nodes 51a, 51b, a coordinate value of the nodes 51a, 51b, and a tread portion. Numerical data such as material properties (for example, density, Young's modulus, damping coefficient, etc.) of the rubber material constituting 1 are defined.

  As shown in FIG. 4, in the rubber model 5, the element 50a forming the first rubber model 5a is a finer element than the element 50b forming the second rubber model 5b. It is preferable that the interval between the provided nodes 51a is smaller than the interval between the nodes 51b provided on the second rubber model 5b.

  The node setting section 12 includes a first node setting section 17 and a second node setting section 18 as shown in FIG. The first node setting unit 17 sets a first node 60 rigidly connected to the stud pin model 4 at a position corresponding to the tip of the stud pin 3 in the stud pin model 4 (see FIG. 3).

  Here, the position corresponding to the tip of the stud pin 3 for setting the first node 60 is a region on the central axis of the stud pin 3 from the end face 3b of the base 3a of the stud pin 3 to the tip of the spike 3c. For example, it can be provided in a region corresponding to a position 5 mm away from the end surface 3b of the base 3a of the stud pin 3 in the direction in which the spike portion 3c protrudes.

  As shown in FIG. 3, the second node setting unit 18 has a different inclination angle with respect to the tire radial direction R in addition to the pull-out direction Pa parallel to the tire radial direction (in other words, the central axis direction of the stud pin 3) R. A plurality of drawing directions Pb to Pm are set. In addition, the second node setting unit 18 assigns a plurality of second nodes 70a to 70m at positions separated by a predetermined distance from the first node 60 in the extraction directions Pa to Pm for each of the set multiple extraction directions Pa to Pm. Set.

  Note that, in the present embodiment, a case will be described in which thirteen pull-out directions Pa to Pm and the second nodes 70a to 70m are set as shown in FIG. 3, but the pull-out direction and the second node set by the second node setting unit 18 are set. The number of nodes can be arbitrarily set to one or more.

  Also, the second node setting unit 18 controls the second nodes 70a to 70m to move only in the corresponding pull-out directions Pa to Pm while keeping the distance between the second nodes 70a to 70m and the first node 60 constant. A constraint condition for restricting the movement of the first node 60 and the second nodes 70a to 70m is set. In other words, the second node 70a moves only in the pull-out direction Pa while maintaining a constant distance from the first node 60, and the other second nodes 70b to 70m are connected to the first node 60 similarly to the second node 70a. The constraint condition is set for each of the second nodes 70a to 70m so as to move only in the corresponding pulling directions Pb to Pm while keeping the distance constant.

  The tire model creating section 13 fits the stud pin model 4 into the stud hole 2 of the rubber model 5 to create a tire model 6 as shown in FIG.

  The reaction force acquiring unit 14 selects one pull-out direction from the plurality of pull-out directions Pa to Pm, moves the stud pin model 4 in the pull-out direction Pa to Pm selected in the tire model 6, and deforms the rubber model 5. Is calculated. Thereby, the reaction force acquisition unit 14 acquires the reaction force generated in the rubber model 5 when the stud pin model 4 is pulled out in the selected drawing direction Pa to Pm. The acquired reaction force corresponds to a pulling force required to pull out the stud pin 3 from the stud hole 2 in the selected pulling direction Pa to Pm.

  The reaction force acquiring unit 14 acquires a reaction force generated in the rubber model 5 when the stud pin model 4 is pulled out for each of the plurality of drawing directions Pa to Pm set in the second node setting unit 18 and calculates the obtained reaction force. The information is stored in the memory in association with the pull-out directions Pa to Pm.

  The analysis unit 20 obtains the minimum reaction force among the reaction forces acquired for each of the plurality of extraction directions Pa to Pm by the reaction force acquisition unit 14 and the extraction direction Pa to Pm that is the minimum reaction force, and displays them. And the like.

  Next, the operation of the device 10 will be described mainly with reference to FIG.

  First, in step S1, the stud pin model acquisition unit 15 acquires the stud pin model 4.

  Next, the rubber model acquisition unit 16 acquires the first rubber model 5a and the second rubber model 5b (Step S2, Step S3), and combines the acquired first rubber model 5a and second rubber model 5b to form the rubber model 5 Is created (step S4).

  Next, in step S5, the first node setting unit 17 sets the first node 60, and the second node setting unit 18 sets the pull-out directions Pa to Pm, the second nodes 70a to 70m, and the constraint conditions.

  Next, in step S6, the tire model creating unit 13 fits the stud pin model 4 into the hole 7 of the rubber model 5 to create a tire model 6 as shown in FIG.

  Next, the reaction force acquiring unit 14 selects one of the pull-out directions Pa to Pm from the plurality of pull-out directions Pa to Pm (Step S7), and then moves the stud pin model 4 to the pull-out direction Pa to Pm selected in the tire model 6. Is moved to calculate the deformation of the rubber model 5, and the reaction force generated in the rubber model 5 is obtained (step S8).

  Next, it is determined whether or not the reaction force generated in the rubber model 5 when the stud pin model 4 is pulled out for all of the plurality of drawing directions Pa to Pm set in the second node setting unit 18 is obtained, and the reaction force is obtained. If the pull-out directions Pa to Pm that have not been performed remain (No in Step S9), the process proceeds to Step S10, and after selecting the pull-out directions Pa to Pm for which the reaction force has not been acquired, the process returns to Step S8 and returns to Step S10. The reaction force generated in the rubber model 5 when the stud pin model 4 is pulled out is obtained for the pulling directions Pa to Pm selected in.

  Then, when the reaction force generated in the rubber model 5 when the stud pin model 4 is pulled out in all the pulling directions Pa to Pm is obtained (Yes in step S9), the process proceeds to step S11, and the analyzing unit 20 sets the pulling directions Pa to Pm. Among the reaction forces acquired for Pm, the output unit outputs the minimum reaction force and the pull-out directions Pa to Pm that provide the minimum reaction force.

  In the device 10 of the present embodiment as described above, the pull-out directions Pa to Pm of the stud pin model 4 are set, and the first node 60 set at a position corresponding to the tip of the stud pin 3 and the first node 60 The second nodes 70a to 70m set at positions away from the pull-out directions Pa to Pm are added, and the second nodes 70a to 70m keep the distance from the first node 60 constant, and the corresponding pull-out directions Pa to Pm, respectively. A tire created by setting the constraint conditions of the first node 60 and the second nodes 70a to 70m so that the second nodes 70a to 70m move only to the stud pin model 4 and the hole 7 of the rubber model 5 In the model 6, the deformation of the rubber model 5 is calculated by moving the stud pin model 4 in the pull-out directions Pa to Pm. Therefore, in the device 10, the pull-out force required to pull out the stud pin 3 from the stud hole 2 in an arbitrary direction can be predicted, and the pull-out resistance performance of the stud pin 3 can be accurately predicted.

  Further, in the present embodiment, the first rubber model 5a in which the stud hole 2 and its periphery are modeled by the element 50a, and the second rubber model 5b in which the tread portion 1 is modeled by the element 50b outside the first rubber model 5a. And a rubber model 5 is obtained. Therefore, when one of the shape of the stud hole 2 and the pattern shape of the tread portion 1 is changed in design, the other model can be used, and the number of work steps required for model optimization can be reduced.

  While some embodiments of the present invention have been described above, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. These embodiments can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the invention described in the claims and equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Tread part, 2 ... Stud hole, 3 ... Stud pin, 3a ... Base part, 3b ... End face, 3c ... Spike part, 4 ... Stud pin model, 5 ... Rubber model, 5a ... First rubber model, 5b ... Second Rubber model, 6 tire model, 10 device, 11 model acquisition unit, 12 node setting unit, 13 tire model creation unit, 14 reaction force acquisition unit, 15 stud pin model acquisition unit, 16 rubber model Acquisition unit, 17 first node setting unit, 18 second node setting unit, 20 analysis unit, 60 first node, 70a to 70m second node

Claims (6)

In a tire simulation method for simulating a pull-out force of a stud pin fitted in a stud hole provided in a tread portion,
Obtaining a stud pin model in which the stud pin is modeled with a finite number of elements,
Acquiring a rubber model in which at least a part of the tread portion including the stud hole is modeled with a finite number of elements,
Setting a first node at a position corresponding to the tip of the stud pin, and rigidly coupling the first node to the stud pin model;
The direction in which the stud pin model is pulled out is set, and a second node is added at a position away from the first node in the direction in which the stud pin model is pulled out, and the distance between the second node and the first node is kept constant. Setting constraint conditions of the first and second nodes so that the second nodes move only in a direction in which the stud pin model is pulled out;
Creating a tire model by fitting the stud pin model into the stud hole of the rubber model;
Calculating the deformation of the rubber model by moving the stud pin model in the pull-out direction in the tire model to obtain a reaction force generated in the rubber model when the stud pin model is pulled out. Simulation method.   The tire simulation method according to claim 1, wherein a direction in which the stud pin model is pulled out is inclined with respect to a tire radial direction. Set multiple directions to pull out the stud pin model,
A second node is set for each of the set plurality of drawing directions,
The tire simulation method according to claim 1 or 2, further comprising a step of acquiring a reaction force generated in the rubber model when the stud pin model is pulled out for each of a plurality of drawing directions.   4. The tire simulation method according to claim 3, further comprising a step of acquiring a minimum reaction force among the reaction forces acquired for each of the plurality of drawing directions and a drawing direction that is the reaction force. 5.   The step of obtaining the rubber model includes the steps of obtaining a first rubber model obtained by modeling the stud hole and the periphery thereof with a finite number of elements, and forming a tread portion with a finite number of elements outside the first rubber model. The method according to any one of claims 1 to 4, further comprising: obtaining a modeled second rubber model; and coupling the first rubber model and the second rubber model to obtain the rubber model. The described tire simulation method. In a tire simulation device that simulates a pull-out force of a stud pin fitted in a stud hole provided in a tread portion,
A stud pin model acquisition unit for acquiring a stud pin model obtained by modeling the stud pin with a finite number of elements,
A rubber model acquisition unit that acquires a rubber model in which at least a part of the tread portion including the stud hole is modeled with a finite number of elements,
A first node setting unit that sets a first node at a position corresponding to the tip of the stud pin, and rigidly couples the first node to the stud pin model;
The direction in which the stud pin model is pulled out is set, and a second node is added at a position away from the first node in the direction in which the stud pin model is pulled out, and the distance between the second node and the first node is kept constant. A second node setting unit that sets constraint conditions of the first node and the second node such that the second node moves only in a direction in which the stud pin model is pulled out;
A tire model creation unit that creates the tire model by fitting the stud pin model into the stud hole of the rubber model;
A reaction force obtaining unit that obtains a reaction force generated in the rubber model when the stud pin model is pulled out by moving the stud pin model in the pulling direction in the tire model and calculating the deformation of the rubber model; A tire simulation device comprising:

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