JP7033018B2 - Tire simulation method and equipment - Google Patents

Description

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

Pneumatic tires with stud pins driven into the surface of the tread are generally called stud tires or studded tires, and are mainly used for running on icy and snowy roads. For studded tires, it is important to improve the retention of the stud pins in order to fully demonstrate the running performance on ice and snow roads.

Therefore, it has been conventionally proposed to predict the pull-out resistance of a stud pin by 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 with a finite number of elements. (For example, see Patent Document 1 below).

JP 2000-238510

However, although the stud pin is subjected to pulling force from various directions other than the tire radial direction when the vehicle is running, Patent Document 1 only considers the case where the stud pin is pulled out in the tire radial direction. .. Moreover, tires usually have grooves and land portions of various shapes formed in the tread portion, and the direction in which the stud pin can be easily pulled out differs depending on these shapes. Therefore, in Patent Document 1, it is difficult to accurately predict the pull-out resistance performance of the stud pin.

Therefore, it is an object of the present invention to provide a tire simulation method and an apparatus capable of accurately predicting the pull-out resistance performance of a stud pin fitted in a stud hole.

The present invention is a step of acquiring a stud pin model in which the stud pin is modeled with a finite number of elements in a tire simulation method for simulating the pulling force of a stud pin fitted in a stud hole provided in a tread portion. A step of 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 a first node is set at a position corresponding to the tip portion of the stud pin. The step of rigidly connecting the first node to the stud pin model and the direction in which the stud pin model is pulled out are set, and the second node is added at a position away from the first node in the direction in which the stud pin model is pulled out. A step of setting constraint conditions for the first node and the second node so that the second node moves only in the direction in which the stud pin model is pulled out while keeping the distance between the second node and the first node constant. And the step of fitting the stud pin model into the stud hole of the rubber model to create a tire model, and moving the tire model in the direction of pulling out the stud pin model to calculate the deformation of the rubber model. By doing so, the reaction force generated in the rubber model when the stud pin model is pulled out is acquired.

According to the present invention, since the pull-out direction of the stud pin can be set in any direction, the pull-out resistance performance of the stud pin can be predicted with high accuracy.

Sectional drawing of the stud hole of a stud pin and a tread part. The figure which shows the simulation apparatus of the tire which concerns on one Embodiment of this invention. The figure which shows the stud pin model schematically. The figure which shows the rubber model schematically. The perspective view which shows an example of the 1st rubber model and the 2nd rubber model. The figure which shows the tire model schematically. FIG. 5 is a flow chart 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 has a stud hole 2 provided in the tread portion 1 and a stud fitted in the stud hole 2 as shown in FIG. In a pneumatic tire provided with a pin 3, the pulling 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 portion 3a fitted in the stud hole 2 of the tread portion 1 and a spike portion 3c protruding outward in the radial direction of the tire from the end surface 3b of the base portion 3a. The spike portion 3c protrudes outward in the tire radial direction from the tread surface 1a of the tread portion 1 and comes into contact with 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. In the model acquisition unit 11, the node setting unit 12, the tire model creation unit 13, and the reaction force acquisition unit 14, the CPU is stored in advance in an information processing device such as a personal computer provided with a CPU, a memory, various interfaces, and the like. Software and hardware are realized in cooperation by executing processing routines (not shown).

The device 10 receives an operation from a user via a known operation unit such as a keyboard or a mouse, and has data on a pneumatic tire and a direction in which the stud pin model 4 is pulled out (hereinafter, may be referred to as a “pulling direction”) Pa. Accepts data settings related to conditions such as ~ Pm, and stores these data in the memory.

The model acquisition unit 11 has a stud pin model acquisition unit 15 that acquires a stud pin model 4 that models the stud pin 3 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 a modeled rubber model 5 is provided.

As shown in FIG. 3, the stud pin model 4 is modeled with 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, but in addition to this, for example, a triangular element having three nodes, a beam element having two nodes, and the like. 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 stud pin model 4 input to the stud pin model acquisition unit 15 in the present embodiment, only the base portion 3a fitted to the stud hole 2 is included in the base portion 3a and the spike portion 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 portion 3a of the stud pin 3 (see FIGS. 3 and 6).

In addition, numerical data such as an element number, a node number 41, a coordinate value of the node 41, and material properties of the stud pin 3 (for example, density, Young's modulus, attenuation coefficient, etc.) are defined in each element 40. 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 whose periphery thereof is modeled by a finite number of elements 50a. The first rubber model 5a having the holes 7 and the second rubber model 5b in which the tread portion 1 is modeled by a finite number of elements 50b on the outside of the first rubber model 5a are coupled.

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

Further, the second rubber model 5b is not particularly limited in its size range as long as it is provided on the outside of the first rubber model 5a, but for example, the stud hole 2 is provided 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 and 50b constituting the first rubber model 5a and the second rubber model 5b has an element number, a node number 51a and 51b, a coordinate value of the node 51a and 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 constituting the first rubber model 5a is a finer element than the element 50b constituting the second rubber model 5b, that is, the first rubber model 5a. It is preferable that the distance between the provided nodes 51a is smaller than the distance between the nodes 51b provided on the second rubber model 5b.

As shown in FIG. 2, the node setting unit 12 includes a first node setting unit 17 and a second node setting unit 18. The first node setting unit 17 sets the first node 60 rigidly coupled 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 corresponding to the tip of the spike portion 3c from the end surface 3b of the base 3a of the stud pin 3 on the central axis of the stud pin 3. For example, it can be provided in a region corresponding to a position 5 mm away from the end surface 3b of the base portion 3a of the stud pin 3 in the protruding direction of the spike portion 3c.

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. Set a plurality of drawing directions Pb to Pm. Further, the second node setting unit 18 sets a plurality of second nodes 70a to 70m at positions separated from the first node 60 by a predetermined distance from the first node 60 for each of the set plurality of extraction directions Pa to Pm. Set.

In the present embodiment, the case where 13 drawing directions Pa to Pm and the second node 70a to 70m are set as shown in FIG. 3 will be described, but the drawing direction and the second node set by the second node setting unit 18 will be described. The number of nodes can be arbitrarily set to be one or a plurality.

Further, the second node setting unit 18 moves the second node 70a to 70m only in the corresponding drawing direction Pa to Pm while keeping the distance from the first node 60 constant. Constraints are set to limit the movement of the first node 60 and the second node 70a to 70m. That is, the second node 70a moves only in the pulling direction Pa while keeping the distance from the first node 60 constant, and the other second nodes 70b to 70m also have the same as the first node 60 as in the second node 70a. Constraints are set for each of the second nodes 70a to 70m so as to move only in the corresponding pull-out directions Pb to Pm while keeping the distance constant.

The tire model creating unit 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 acquisition unit 14 selects a pull-out direction of 1 from a plurality of set pull-out directions Pa to Pm, and moves the stud pin model 4 to the pull-out directions Pa to Pm selected in the tire model 6 to deform the rubber model 5. To calculate. As a result, 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 pulling direction Pa to Pm. The acquired reaction force corresponds to the 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 acquisition unit 14 acquires the reaction force generated in the rubber model 5 when the stud pin model 4 is pulled out for each of the plurality of pull-out directions Pa to Pm set in the second node setting unit 18, and obtains the acquired reaction force. It is stored in the memory in association with the pulling directions Pa to Pm.

The analysis unit 20 acquires the minimum reaction force among the reaction forces acquired in each of the plurality of pull-out directions Pa to Pm by the reaction force acquisition unit 14, and the pull-out direction Pa to Pm which is the minimum reaction force, and displays these. Output from the output section such as.

Next, the operation of the apparatus 10 will be described mainly with reference to FIG. 7.

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 (steps S2 and S3), and the acquired first rubber model 5a and the second rubber model 5b are combined 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 drawing direction Pa to Pm, the second node 70a to 70m, and the constraint condition.

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 the tire model 6 as shown in FIG.

Next, the reaction force acquisition unit 14 selects one pulling direction Pa to Pm from the plurality of pulling directions Pa to Pm (step S7), and then the stud pin model 4 goes to the pulling 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 acquired (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 is acquired for all of the plurality of extraction directions Pa to Pm set in the second node setting unit 18, and the reaction force is acquired. If the unpulled pulling directions Pa to Pm remain (No in step S9), the process proceeds to step S10, the pulling directions Pa to Pm for which the reaction force has not been acquired are selected, and then the process returns to step S8 and step S10. Acquires the reaction force generated in the rubber model 5 when the stud pin model 4 is pulled out with respect to 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 acquired (Yes in step S9), the process proceeds to step S11, and the analysis unit 20 moves in the pulling direction Pa to Pm. Of the reaction forces acquired for Pm, the minimum reaction force and the pull-out direction Pa to Pm, which is the minimum reaction force, are output from the output unit.

In the device 10 of the present embodiment as described above, from the first node 60 and the first node 60, in which the pull-out directions Pa to Pm of the stud pin model 4 are set and set at positions corresponding to the tip portions of the stud pins 3. The second node 70a to 70m set at a position distant from the pulling direction Pa to Pm is added, and the second node 70a to 70m keeps a constant distance from the first node 60, and the corresponding pulling directions Pa to Pm respectively. A tire created by setting restraint conditions for the first node 60 and the second node 70a to 70m so that the second node 70a to 70m moves only to the tire, and fitting the stud pin model 4 into the hole 7 of the rubber model 5. In the model 6, the stud pin model 4 is moved in the pulling directions Pa to Pm to calculate the deformation of the rubber model 5. Therefore, in the device 10, the pulling force required for pulling out the stud pin 3 from the stud hole 2 in an arbitrary direction can be predicted, and the pulling resistance performance of the stud pin 3 can be predicted with high accuracy.

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 are combined to obtain the rubber model 5. Therefore, when either the shape of the stud hole 2 or the pattern shape of the tread portion 1 is redesigned, the other model can be used, and the work man-hours required for model optimization can be reduced.

Although some embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

1 ... tread part, 2 ... stud hole, 3 ... stud pin, 3a ... base, 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 ... 1st node setting unit, 18 ... 2nd node setting unit, 20 ... Analysis unit, 60 ... 1st node, 70a-70m ... 2nd node

Claims (6)

In a tire simulation method that simulates the pulling force of a stud pin fitted in a stud hole provided in a tread portion.
The step of acquiring a stud pin model in which the stud pin is modeled with a finite number of elements,
A step of acquiring a rubber model in which at least a part of the tread portion including the stud hole is modeled by a finite number of elements, and
A step of setting a first node at a position corresponding to the tip of the stud pin and rigidly connecting the first node to the stud pin model.
The direction in which the stud pin model is pulled out is set, the 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. While setting the constraint conditions for the first node and the second node so that the second node moves only in the direction in which the stud pin model is pulled out,
A step of fitting the stud pin model into the stud hole of the rubber model to create a tire model, and
A tire including a step of acquiring 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 and calculating the deformation of the rubber model in the tire model. Simulation method. The tire simulation method according to claim 1, wherein the direction in which the stud pin model is pulled out is inclined with respect to the tire radial direction. Set multiple directions for pulling out the stud pin model,
Set the second node for each of the set multiple pulling 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 in each of a plurality of pulling directions. The tire simulation method according to claim 3, further comprising a step of acquiring the minimum reaction force among the reaction forces acquired for each of a plurality of pull-out directions and the pull-out direction that becomes the reaction force. The step of acquiring the rubber model is a step of acquiring a first rubber model in which the stud hole and its surroundings are modeled with a finite number of elements, and a step of acquiring a tread portion with a finite number of elements outside the first rubber model. The item according to any one of claims 1 to 4, further comprising a step of acquiring the modeled second rubber model and a step of combining the first rubber model and the second rubber model to acquire the rubber model. The described tire simulation method. In a tire simulation device that simulates the pulling force of a stud pin fitted in a stud hole provided in a tread portion.
A stud pin model acquisition unit that acquires a stud pin model that models 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, and a rubber model acquisition unit.
A first node setting unit that sets a first node at a position corresponding to the tip of the stud pin and rigidly connects the first node to the stud pin model.
The direction in which the stud pin model is pulled out is set, the 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. At the same time, the second node setting unit that sets the constraint conditions of the first node and the second node so that the second node moves only in the direction in which the stud pin model is pulled out.
A tire model creating unit that creates a tire model by fitting the stud pin model into the stud hole of the rubber model.
A reaction force acquisition unit that acquires 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. Tire simulation device equipped with.

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