JP6045900B2 - Prediction method for tire ground contact edge shape, tire ground contact edge shape prediction device, and tire ground contact edge prediction program - Google Patents

Description

  The present invention relates to a method for predicting a contact end shape in consideration of a centrifugal force corresponding to a tire rotation speed, a prediction device for a contact end shape, and a program for predicting a contact end shape.

  The shape of the ground contact surface of a tire in contact with the road surface is often predicted by computer simulation. The main method of predicting the tire contact surface shape is to use a numerical analysis method such as a finite element method (FEM) that divides the tire into a plurality of elements and solves the equation of motion for each element. Conduct ground plane analysis under analysis conditions such as internal pressure.

  It is known that the tire contact surface shape, that is, the contact end shape that becomes the boundary of the contact surface on the tire front-rear direction differs depending on the speed because the centrifugal force varies depending on the speed. For example, Patent Document 1 discloses a technique for calculating a tire ground contact end shape by applying a load of a centrifugal force component corresponding to a preset tire rotation speed to a tire finite element model.

JP 2005-75296 A

  In order to reproduce tire usage as much as possible, considering the fact that tire rotation speed changes significantly as the vehicle accelerates and decelerates, predict the contact end shape considering centrifugal force for each rotation speed to be analyzed. Is required.

  However, in the conventional method for predicting the contact end shape, since the contact end shape by the finite element method must be sequentially calculated for each rotational speed to be analyzed, the calculation cost increases as the rotational speed to be analyzed increases. .

  The present invention has been made paying attention to such problems, and its purpose is to predict the shape of the ground contact edge at an arbitrary rotational speed without performing ground contact analysis for all rotational speeds to be analyzed. To provide a prediction method, a prediction device, and a prediction program for a tire ground contact end shape that can be realized.

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

That is, the tire ground contact end shape prediction method of the present invention,
It is a reference point for expressing the contact end shape of the contact analysis result at a certain rotational speed using a tire finite element model by an interpolation method, and is arranged for each reference position set in a plurality of locations in the tire width direction. A plurality of reference points as one set, obtaining ground contact data based on the coordinate values of each reference point when a predetermined number of sets are provided with different rotational speeds;
Using the ground contact edge data, the coordinate values of a plurality of reference points serving as base points for calculation of the shape of the ground contact edge at a desired rotational speed are represented by coordinate values of reference points at rotational speeds other than the desired rotational speed at the respective reference positions. Calculating by approximating
Interpolating the plurality of calculated reference points to calculate a ground contact end shape at the desired rotational speed.

In addition, the tire ground contact end shape prediction device of the present embodiment,
It is a reference point for expressing the contact end shape of the contact analysis result at a certain rotational speed using a tire finite element model by an interpolation method, and is arranged for each reference position set in a plurality of locations in the tire width direction. A data acquisition unit that acquires a plurality of reference points as one set, acquires ground contact data based on the coordinate values of each reference point when a predetermined number of sets are provided with different rotational speeds, and
Using the grounding edge data acquired by the grounding edge data, the coordinate values of a plurality of reference points serving as the base points for calculation of the grounding edge shape at a desired rotational speed are determined as rotational speeds other than the desired rotational speed at each reference position. A reference point calculation unit for calculating by approximating the coordinate value of the reference point in
A ground contact end shape calculating unit that calculates the contact end shape at the desired rotation speed by interpolating the plurality of calculated reference points.

  The ground contact end data means that it may be data based on the coordinate values of a plurality of reference points with different rotation speeds. For example, it may be data representing the coordinate values of these reference points, or approximate expression data or interpolation expression data derived from the coordinate values of these reference points. The approximate expression data includes, for example, approximate expression data for calculating the coordinate values of a plurality of reference points at a desired rotational speed from the coordinate values of the reference points at other rotational speeds. The interpolation data includes, for example, interpolation data for deriving the ground contact end shape from a plurality of reference points at a certain rotational speed.

  The acquisition of the ground contact edge data includes generating the ground contact edge data by performing a ground contact analysis using a tire finite element model, and acquiring the already generated ground contact edge data from the storage unit.

  By using such ground contact edge data, it is possible to express the ground contact edge shape at a certain rotational speed by an interpolation method using a set of reference points arranged for each reference position. The coordinate value can be calculated by approximation based on the coordinate value of the reference point at another rotational speed. Therefore, the grounding end shape of the rotational speed for which the grounding analysis is not actually performed can be calculated based on the coordinate value of the reference point representing the grounding end shape at the other rotational speeds analyzed for grounding, and the grounding of the desired rotational speed to be analyzed Compared with the case where all analyzes are performed, the calculation cost can be significantly reduced.

In the above method, in order to minimize the number of times of grounding analysis and to be able to effectively calculate the grounding edge shape whose accuracy is within the allowable range,
Performing a ground contact analysis using a tire finite element model for a given upper limit rotational speed and lower limit rotational speed and an intermediate speed thereof, and calculating a ground contact end actual shape at each rotational speed;
The coordinate value of the ground contact end predicted shape and the coordinate value of the ground contact end actual shape expressed by an interpolation formula that interpolates between the reference points using the actual coordinate values at the reference points arranged for each preset reference position. Performing a process of adding a new reference position until the error of becomes smaller than the first threshold;
For each reference position, by approximating the actual coordinate value at the rotational speed at which the grounding analysis was performed, the predicted coordinate value at the rotational speed at which the grounding analysis was not performed was calculated with an approximate expression, and the grounding analysis at the rotational speed was performed. Performing a grounding analysis at a new rotational speed until an error between the actual coordinate value obtained by performing and the predicted coordinate value becomes smaller than a second threshold;
It is preferable to generate the ground end data by executing

  In the above apparatus, in order to minimize the number of times of grounding analysis and to be able to effectively calculate a grounding end shape whose accuracy is within an allowable range, the data acquisition unit executes the above steps to execute the grounding end data. Is preferably generated.

  In order to improve the calculation accuracy of the contact end shape by interpolation, the contact end shape is preferably expressed for each rib or block row partitioned in the tire width direction by grooves extending in the tire front-rear direction.

  In the present invention, the steps constituting the above method can be specified from the viewpoint of a program.

That is, the tire ground contact end shape prediction program of the present invention,
It is a reference point for expressing the contact end shape of the contact analysis result at a certain rotational speed using a tire finite element model by an interpolation method, and is arranged for each reference position set in a plurality of locations in the tire width direction. A plurality of reference points as one set, obtaining ground contact data based on the coordinate values of each reference point when a predetermined number of sets are provided with different rotational speeds;
Using the ground contact edge data, the coordinate values of a plurality of reference points serving as base points for calculation of the shape of the ground contact edge at a desired rotational speed are represented by coordinate values of reference points at rotational speeds other than the desired rotational speed at the respective reference positions. Calculating by approximating
And interpolating the plurality of calculated reference points to cause the computer to execute the step of calculating the ground contact end shape at the desired rotational speed. By executing this program, the operational effects produced by the above method can be obtained.

The block diagram which shows typically the prediction apparatus of the tire grounding end shape which concerns on this invention. The figure which shows an example of the contact-surface shape which is a contact-analysis result using a tire finite element model. The figure which expressed the grounding end shape of FIG. 2A by the line segment. The figure which shows the earthing | grounding end shape obtained by interpolating a some reference point. The figure which shows the difference | error of the predicted shape and actual shape of the grounding end estimated by interpolation of a reference point. Explanatory drawing regarding the ground end data. The figure which shows the relationship between the coordinate value of the reference point in a certain reference position, and rotational speed. The figure which shows the difference | error of the actual coordinate value of the reference point in a certain reference position, and the predicted coordinate value obtained by approximation. Explanatory drawing regarding calculation of the contact end shape at a desired rotation speed. The flowchart which shows the prediction method of a tire ground-contact end shape.

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

[Tire contact end shape prediction device]
A tire ground contact end shape prediction device 2 of the present invention shown in FIG. 1 is a device that predicts the tire ground contact end shape using computer simulation under conditions of a predetermined load, a predetermined internal pressure, and a rotational speed.

  FIG. 2A is a diagram illustrating an example of a contact surface shape that is an analysis result obtained by performing a contact analysis using a tire finite element model. As shown in FIG. 2A, the ground contact surface extends in the tire width direction WD and the tire longitudinal direction CD. In this specification, the interface in the tire front-rear direction CD among the ground contact surfaces of the tire is handled as a ground contact end. The ground contact end shape is represented by a line segment as shown in FIG. 2B.

  Specifically, the tire ground contact end shape prediction device 2 includes an initial setting unit 20, a data acquisition unit 21, a reference point calculation unit 22, and a ground contact end shape calculation unit 23, as shown in FIG. The data acquisition unit 21 includes a ground contact analysis unit 24, a shape prediction unit 25, a shape prediction evaluation unit 26, a reference point prediction unit 27, and a reference point prediction evaluation unit 28. These units 20 to 28 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 initial setting unit 20 shown in FIG. 1 receives an operation from a user via a known operation unit such as a keyboard or a mouse, and an upper limit rotation used for setting and analysis regarding a tire finite element model to be analyzed. Various analysis conditions required for simulation using the finite element method such as speed and lower limit rotation speed, rotation speed to be analyzed, and load value applied to the tire model are set, and these setting values are stored in a memory (not shown). To do. The tire finite element (FE) model is composed of a finite number of elements divided by element division (for example, mesh division) corresponding to the finite element method.

  The data acquisition unit 21 shown in FIG. 1 has a grounding end necessary for predicting a grounding end shape of a desired rotational speed Vref within a range defined by an upper limit rotational speed Vmax and a lower limit rotational speed Vmin given in advance as parameters. Generate or acquire data.

Hereinafter, the ground end data will be described.
The ground end shape can be expressed by a line segment as shown in FIG. 2B, and the line segment is defined between a plurality of reference points (P ₁ , P ₂ , P ₃ ) arranged on the line segment as shown in FIG. 3A. It can be expressed by interpolation using an interpolation method such as spline interpolation. Further, as shown in FIG. 4, the contact end shape changes in the tire longitudinal direction CD according to the speed (V _{1 to} V _n : n is a natural number), and therefore, for example, a reference point P on a certain reference position B _{5 No. 5} , even if the speed changes, the coordinate value x in the tire width direction WD does not change, and only the coordinate value y in the tire longitudinal direction CD changes. Therefore, the relationship between the coordinate value y of the speed and the tire longitudinal direction CD at a certain reference position _{B 5,} as shown in FIG. 5A, with respect to the coordinate value y of the reference point ^{(P V1, P V2, P} V4) It can be expressed by an approximate expression.

Ground terminal data intended to be generated by utilizing the above characteristics, a data based on the coordinate values of each reference point P ^Vj _i shown in FIG. P ^Vj represents a reference point at the rotational speed V _j . P _i represents a reference point at the reference position B _i . i = 1 to m and j = 1 to n. The predetermined number n is a number obtained by performing the ground contact analysis with different rotation speeds, and m represents the number of reference positions. That is, it is a reference point P ^Vj for expressing the contact end shape of the contact analysis result at a certain rotational speed V _j using the tire finite element model by an interpolation method, and is set at a plurality of locations in the tire width direction WD. When a plurality of reference points (P ^Vj _{1 to} P ^Vj _m ) arranged at each reference position (B _{1 to} B _m ) are set as one set, and a predetermined number n sets are provided with different rotational speeds V _j is data based on the coordinate values of each reference point ^{_P V1~n} _1~m.

The data based on the coordinate values, it is meant that may be a data calculated based on the coordinate values of the plurality of reference points ^P V1~n _1~m having different rotational speed. For example, be the data itself representing the coordinate values of the plurality of reference points ^P V1~n _1~m, it may be approximate expression data or interpolation equation data derived from these coordinate values. The approximate expression data includes, for example, approximate expression data for calculating the coordinate values of a plurality of reference points at a desired rotational speed from the coordinate values of the reference points at other rotational speeds. The interpolation data includes, for example, interpolation data for deriving the ground contact end shape from a plurality of reference points at a certain rotational speed. Further, if the desired rotational speed is input as a parameter, including interpolation formulas and approximation formulas, formula data such as a polynomial that outputs the ground contact end shape may be used.

The reference point calculation unit 22 shown in FIG. 1 uses the ground contact end data and, as illustrated in FIG. 6, a plurality of reference points P ^Vref _{1 to 5} (reference points for calculation of the ground contact end shape at a desired rotation speed Vref). Reference values P ^{V1 to n} _1-5 at the rotation speeds other than the desired rotation speed Vref at the respective reference positions B _{1 to 5} (indicated by circles in the figure) It is calculated by approximating the coordinate value of.

  As shown in FIG. 6, the contact edge shape calculation unit 23 shown in FIG. 1 interpolates a plurality of reference points (indicated by triangles in the figure) calculated by the reference point calculation unit 22 by an interpolation method such as spline interpolation. Thus, the ground contact end shape Sref at the desired rotation speed Vref is calculated.

  Since the grounding end data represents the grounding end shape based on interpolation and approximation between reference points, the predicted grounding end shape and the actual grounding end shape by grounding analysis include at least some errors. Therefore, in order to reduce the error to an allowable range, the data acquisition unit 21 includes the units 24 to 28, and generates the ground end data as described below.

  The ground contact analysis unit 24 performs a ground contact analysis using the tire finite element model under analysis conditions including a preset tire finite element model, a predetermined load, a predetermined internal pressure, and a rotational speed, and calculates a contact end shape.

The shape predicting unit 25 calculates a ground contact end predicted shape S expressed by an interpolation formula for interpolating between the reference points using the actual coordinate values at the reference points arranged for each preset reference position B _i. . The actual coordinate value is a value of the contact end shape calculated by the contact analysis unit 24. As illustrated in FIG. 3A, in the case of three reference positions, the ground contact end shape S is calculated using the actual coordinate values of the reference points P1 to _P3 . The initial value of the reference position is the both ends of the ground contact end shape and the midpoint of the both ends.

The shape prediction evaluation unit 26 can also be called an interpolation type evaluation unit that evaluates the validity of the predicted contact end shape S calculated by the shape prediction unit 25 using an interpolation formula. Therefore, the shape prediction evaluation unit 26 determines that the error between the coordinate value of the predicted contact end shape S calculated by the shape prediction unit 25 and the coordinate value of the actual contact end shape R calculated by the contact analysis unit 24 is the first threshold value U1. ^It is determined whether or not it is smaller than ² . Specifically, if there are three reference positions shown in FIG. 3A, a new reference position B ₄ is added as shown in FIG. 3B, and a reference point P ′ ₄ at the reference position B ₄ is calculated by the interpolation method. To do. The new reference position is set in the middle between the existing reference positions. Next, it is determined whether the error D1 coordinate values of the reference point P _'4 coordinate values and the actual shape reference point P ₄ of the predicted shape is smaller than the first threshold value U1 ^2. When the condition is not satisfied, the predicted shape S is not valid, and when the condition is satisfied, the predicted shape S is valid. Discriminant is _{(P 'i + 1 -P i} + 1) 2 <U1 2. P _{i + 1} is a ground end coordinate value of the finite element analysis result, and P ′ _{i + 1} is a value predicted by interpolation from the coordinate values of P ₁ to _i . The threshold value U1 is set to a value of 2 to 5% of the contact length, but can be variously changed according to the analysis request. 3A and 3B are drawings for explanation, they do not coincide with FIG.

  The process of adding a new reference position is repeated until the determination result of the shape prediction evaluation unit 26 is established. That is, the number of reference positions necessary for the error to fall within the allowable range is determined.

The reference point prediction unit 27 shown in FIG. 1 approximates the predicted coordinate value at the rotational speed at which the ground contact analysis is not performed by approximating the actual coordinate value at the rotational speed at which the ground contact analysis is performed at each reference position. Calculate with For example, in the example of the reference position _{B 5,} as shown in Figure 5B, to approximate the actual coordinate values of the rotation speed performed ground analysis _{(V 1, V 2, V} 4) (P V1, P V2, P V3) it allows to calculate the predicted coordinate value P ^'V3 in the rotation speed V ₃ that have not performed the ground analysis.

The reference point prediction evaluation unit 28 shown in FIG. 1 can also be called an approximate expression evaluation unit that evaluates the validity of the approximate expression calculated by the reference point prediction unit 27. Therefore, whether or not the error D2 between the actual coordinate value P ^V3 of the reference position B ₅ and the predicted coordinate value obtained by performing the contact analysis at the rotation speed V ₃ is smaller than the second threshold value U 22 ^2. Determine whether. When the condition is not satisfied, the approximate expression is not valid, and when the condition is satisfied, the approximate expression is valid. The discriminant is 1 / m × Σ (P′V ^{(j + 1)} −PV ^{(j + 1)} ) ² <U2 ² . P ^{V (j + 1)} is a ground end coordinate value of the finite element analysis result of the rotational speed V _{(j + 1)} , and P ′ ^{V (j + 1)} is a value predicted by an approximate expression from coordinate values from P ^{V1 to} P ^Vj. It becomes. The threshold value U2 is set to a value of 2 to 5% of the contact length, but can be variously changed according to the analysis request.

  The grounding analysis at the new rotation speed is performed until the determination result of the reference point prediction / evaluation unit 28 is established. That is, the grounding analysis is performed as many times as necessary until the error falls within the allowable range.

  In the present embodiment, as shown in FIGS. 2A and 2B, the ground contact end shape is expressed for each rib or block row partitioned in the tire width direction WD by the groove 10 extending in the tire longitudinal direction CD. For example, since the present embodiment has five ribs as shown in the figure, the ground contact end shape of each rib is expressed by five interpolation equations.

[Tire contact end shape prediction method]
A method of predicting the tire ground contact end shape using the prediction device 2 will be described with reference mainly to the flowchart of FIG.

  First, in step ST1, the initial setting unit 20 shown in FIG. 1 accepts a user operation via an operation unit (not shown), and the tire model, the upper limit rotation speed Vmax, the lower limit rotation speed Vmin, and the desired rotation to be analyzed. Various settings required for simulation such as speed Vref are performed.

  In the next step ST2, the ground contact analysis unit 24 shown in FIG. 1 generates a three-dimensional tire finite element model based on the set value. In the next step ST3, the ground contact analysis unit 24 performs a ground contact analysis on the given upper limit rotational speed Vmax and lower limit rotational speed Vmin and their intermediate speeds using a tire finite element model, and the ground contact actual at each rotational speed. Calculate the shape.

In the next step ST4, the shape prediction unit 25 shown in FIG. 1 acquires the coordinate values of three reference points including both ends for each rib at each speed. In this case, the initial reference position is set to three, and the coordinate value of the reference point at each reference position is acquired. In the next step ST5, shape prediction unit 25, for example, as shown in FIG. 3A, a coordinate group P _{1 to 3} and spline interpolation, to calculate the ground terminal predicted shape S. In the next step ST6, the shape prediction unit 25 adds a new reference position and predicts the coordinate value of the reference point at the reference position, as shown in FIG. 3B. In next step ST7, the shape prediction evaluation unit 26 determines whether an error between the coordinate value predicted by interpolation and the coordinate value of the analysis result is smaller than the first threshold value. Until the condition is satisfied in step ST7 (ST7: NO), steps ST5 to ST7 are repeated to add a new reference position.

  That is, by executing the above-mentioned steps ST5 to ST7, the ground contact end prediction expressed by the interpolation formula for interpolating between the reference points using the actual coordinate values at the reference points arranged for each preset reference position. A process of adding a new reference position is executed until an error between the coordinate value of the shape and the coordinate value of the actual contact end actual shape becomes smaller than the first threshold value.

If it is determined in step ST7 that the condition is satisfied (ST7: YES), in the next step ST8, the reference point predicting unit 27 calculates the grounding end from the interpolation formula representing the grounding end for each speed for each reference position. A speed-dependent approximate expression (see the curve in FIG. 5A) is derived, and a predicted coordinate value at a new rotational speed is calculated. That is, as illustrated in FIG. 5B, the reference point prediction unit 27 approximates the actual coordinate values at the rotation speeds (V ₁ , V ₂ , V ₄ ) analyzed for grounding, so that the grounding analysis is not performed. The predicted coordinate value P ′ ^V3 at the speed _V3 is calculated by an approximate expression.

In the next step ST9, the ground contact analysis unit 24 performs the ground contact analysis at the new rotational speed V ₃ to obtain the actual coordinate value P ^V3 shown in FIG. 5B. In the next step ST10, the reference point prediction unit 27 determines whether the error of the predicted coordinate value P ^'V3 and the actual coordinate values ^{P V3} is smaller than the second threshold value U2 ² at the new rotational speed _{V 3.} Until the condition is satisfied in step ST10 (ST10: NO), steps ST8 to 10 are repeated, and a grounding analysis of a new rotational speed is performed.

  That is, by executing steps ST8 to ST10 above, by approximating the actual coordinate value at the rotational speed at which the grounding analysis was performed for each reference position, the predicted coordinate value at the rotational speed at which the grounding analysis was not performed is obtained. A process of performing a grounding analysis at a new rotational speed is executed until the error between the actual coordinate value calculated by the approximate expression and performing the grounding analysis at the rotational speed and the predicted coordinate value becomes smaller than the second threshold value. Is done.

The ground end data is generated as described above. In the next step ST11, the reference point calculation unit 22 shown in FIG. 1 uses the ground contact end data (coordinate values of each reference point, interpolation formula data and approximate data), for example, as shown in FIG. Coordinate values of a plurality of reference points P ^Vref _{1 to 5} (indicated by triangles in the figure), which are the base points for calculating the ground contact end shape at ^Vref , are set to values other than the desired rotational speed Vref at each reference position B _{1 to 5} . Calculation is performed by approximating the coordinate values of the reference points P ^{V1 to n} _1-5 (indicated by circles in the figure) at the rotation speed.

In the next step ST12, the ground end shape calculation unit 23 shown in FIG. 1 performs the spline interpolation between the reference points P ^Vref ₁ to ₅ calculated by the reference point calculation unit 22, as shown in FIG. Sref is calculated.

  If the prediction apparatus 2 and the prediction method described above are implemented, for example, in order to predict the ground contact end shape of 17 stages of rotation speed, a ground analysis of 5 stages of rotation speed is sufficient, and the contact form of the remaining 12 stages of rotation speed is I was able to predict. Therefore, the calculation cost could be reduced to about 30%.

As described above, the tire ground contact end shape prediction method according to the present embodiment uses the interpolation point to represent the contact end shape of the contact analysis result at a certain rotational speed V using the tire finite element model. in it and each reference position set at a plurality of positions in the tire width direction WD _(B 1 _{~B m)} a plurality of reference points P _{1 to m} which are arranged in the one set, a predetermined number of with different rotational speed Obtaining ground contact data based on the coordinate value P ^Vj _i of each reference point when the set n is provided (ST2 to 10);
Using the ground contact edge data, the coordinate values of a plurality of reference points serving as base points for calculation of the ground contact edge shape at the desired rotational speed Vref are used as reference values at rotational speeds other than the desired rotational speed Vref at the respective reference positions _{B1 to B5} . A step of calculating by approximating the coordinate value of the point (ST11);
Calculating a ground contact end shape at the desired rotation speed by interpolating the plurality of calculated reference points (ST12).

The tire ground contact edge shape prediction device 2 according to the present embodiment is a reference point P for expressing the ground contact edge shape of the ground contact analysis result at a certain rotational speed V using a tire finite element model by an interpolation method. and each reference position set at a plurality of positions in the tire width direction WD and _(B 1 _{~B m)} set a plurality of reference points P _{1 to m} which are arranged in, at different rotational speeds of the predetermined number n set The data acquisition unit 21 that acquires the ground contact end data based on the coordinate value P ^Vj _i of each reference point and the ground contact end data acquired by the data acquisition unit 21 is used to form the contact end shape at a desired rotational speed Vref. A reference point calculation unit 22 that calculates the coordinate values of a plurality of reference points serving as base points for the calculation by approximating the coordinate values of the reference points at rotational speeds other than the desired rotational speed at the respective reference positions; Interpolate multiple reference points By doing so, a grounding end shape calculating unit 23 that calculates a grounding end shape at a desired rotation speed Vref is provided.

  The ground contact end data means that it may be data based on the coordinate values of a plurality of reference points with different rotation speeds. For example, it may be data representing the coordinate values of these reference points, or approximate expression data or interpolation expression data derived from the coordinate values of these reference points. The approximate expression data includes, for example, approximate expression data for calculating the coordinate values of a plurality of reference points at a desired rotational speed from the coordinate values of the reference points at other rotational speeds. The interpolation data includes, for example, interpolation data for deriving the ground contact end shape from a plurality of reference points at a certain rotational speed.

  The acquisition of the ground contact edge data includes performing the ground contact analysis using the tire finite element model to generate the ground contact edge data, and acquiring the already generated ground contact edge data from the storage unit. In the present embodiment, data is generated by performing a grounding end analysis.

  By using such ground contact edge data, it is possible to express the ground contact edge shape at a certain rotational speed by an interpolation method using a set of reference points arranged for each reference position. The coordinate value can be calculated by approximation based on the coordinate value of the reference point at another rotational speed. Therefore, the grounding end shape of the rotational speed for which the grounding analysis is not actually performed can be calculated based on the coordinate value of the reference point representing the grounding end shape at the other rotational speeds analyzed for grounding, and the grounding of the desired rotational speed to be analyzed Compared with the case where all analyzes are performed, the calculation cost can be significantly reduced.

Further, in the present embodiment, a step of performing a ground contact analysis using a tire finite element model for the given upper limit rotational speed Vmax and lower limit rotational speed Vmin and their intermediate speeds, and calculating a ground contact end actual shape at each rotational speed. (ST3) and
The coordinate value of the ground contact end predicted shape and the coordinate value of the ground contact end actual shape expressed by an interpolation formula that interpolates between the reference points using the actual coordinate values at the reference points arranged for each preset reference position. Performing a process of adding a new reference position until the error becomes smaller than the first threshold (ST5 to 7),
For each reference position, by approximating the actual coordinate value at the rotational speed at which the grounding analysis was performed, the predicted coordinate value at the rotational speed at which the grounding analysis was not performed was calculated with an approximate expression, and the grounding analysis at the rotational speed was performed. Step (ST8-10) of performing grounding analysis at a new rotational speed until an error between the actual coordinate value obtained and the predicted coordinate value becomes smaller than a second threshold value (ST8 to 10), Is generated.

  In this way, the reference position is added until the error of the contact end shape expressed by the interpolation between the reference points falls within the allowable range, and the rotation speed that is not analyzed based on the reference point data of the rotation speed that is analyzed for contact. Since the grounding analysis data is increased until the error when the reference point is approximated is within the allowable range, the number of grounding analysis can be minimized and the grounding end shape with the accuracy within the allowable range can be calculated effectively. Become.

  Further, in the present embodiment, the ground contact end shape is expressed for each rib or block row partitioned in the tire width direction WD by the groove 10 extending in the tire longitudinal direction CD. Since the contact end shape changes according to the speed change in units of ribs or block rows, it is possible to improve the calculation accuracy of the contact end shape by interpolation rather than handling the entire tire as one contact end shape.

The tire ground contact end shape prediction program according to the present embodiment is a program that causes a computer to execute each step of the tire contact end shape prediction 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 invention was described based on drawing, it should be thought that a specific structure is not limited to these embodiment. The scope of the present invention is shown 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.

  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 invention.

P ... Reference point B 1 to _m ... Reference position 21 ... Data acquisition unit 22 ... Reference point calculation unit 23 ... Grounding end shape calculation unit

Claims (7)

It is a reference point for expressing the contact end shape of the contact analysis result at a certain rotational speed using a tire finite element model by an interpolation method, and is arranged for each reference position set in a plurality of locations in the tire width direction. A plurality of reference points as one set, obtaining ground contact data based on the coordinate values of each reference point when a predetermined number of sets are provided with different rotational speeds;
Using the ground contact edge data, the coordinate values of a plurality of reference points serving as base points for calculation of the shape of the ground contact edge at a desired rotational speed are represented by coordinate values of reference points at rotational speeds other than the desired rotational speed at the respective reference positions. Calculating by approximating
And a step of calculating a ground contact end shape at the desired rotational speed by interpolating a plurality of calculated reference points. Performing a ground contact analysis using a tire finite element model for a given upper limit rotational speed and lower limit rotational speed and an intermediate speed thereof, and calculating a ground contact end actual shape at each rotational speed;
The coordinate value of the ground contact end predicted shape and the coordinate value of the ground contact end actual shape expressed by an interpolation formula that interpolates between the reference points using the actual coordinate values at the reference points arranged for each preset reference position. Performing a process of adding a new reference position until the error of becomes smaller than the first threshold;
For each reference position, by approximating the actual coordinate value at the rotational speed at which the grounding analysis was performed, the predicted coordinate value at the rotational speed at which the grounding analysis was not performed was calculated with an approximate expression, and the grounding analysis at the rotational speed was performed. Performing a grounding analysis at a new rotational speed until an error between the actual coordinate value obtained by performing and the predicted coordinate value becomes smaller than a second threshold;
The tire ground contact edge shape prediction method according to claim 1, wherein the ground contact edge data is generated by executing the following.   The method for predicting a tire ground contact end shape according to claim 1 or 2, wherein the ground contact end shape is expressed for each rib or block row partitioned in a tire width direction by a groove extending in a tire longitudinal direction. It is a reference point for expressing the contact end shape of the contact analysis result at a certain rotational speed using a tire finite element model by an interpolation method, and is arranged for each reference position set in a plurality of locations in the tire width direction. A data acquisition unit that acquires a plurality of reference points as one set, acquires ground contact data based on the coordinate values of each reference point when a predetermined number of sets are provided with different rotational speeds, and
Using the ground contact edge data acquired by the data acquisition unit, the coordinate values of a plurality of reference points serving as the base points for calculation of the ground contact end shape at a desired rotational speed are calculated as rotational speeds other than the desired rotational speed at each reference position. A reference point calculation unit for calculating by approximating the coordinate value of the reference point in
A ground contact end shape calculation unit that calculates a contact end shape at the desired rotation speed by interpolating the plurality of calculated reference points;
A tire ground contact end shape predicting device. The data acquisition unit
Performing a ground contact analysis using a tire finite element model for a given upper limit rotational speed and lower limit rotational speed and an intermediate speed thereof, and calculating a ground contact end actual shape at each rotational speed;
The coordinate value of the ground contact end predicted shape and the coordinate value of the ground contact end actual shape expressed by an interpolation formula that interpolates between the reference points using the actual coordinate values at the reference points arranged for each preset reference position. Performing a process of adding a new reference position until the error of becomes smaller than the first threshold;
For each reference position, by approximating the actual coordinate value at the rotational speed at which the grounding analysis was performed, the predicted coordinate value at the rotational speed at which the grounding analysis was not performed was calculated with an approximate expression, and the grounding analysis at the rotational speed was performed. Performing a grounding analysis at a new rotational speed until an error between the actual coordinate value obtained by performing and the predicted coordinate value becomes smaller than a second threshold;
The tire ground contact edge shape prediction device according to claim 4, wherein the ground contact edge data is generated by executing the following.   The tire contact end shape prediction device according to claim 4 or 5, wherein the contact end shape is expressed for each rib or block row partitioned in the tire width direction by a groove extending in the tire longitudinal direction. It is a reference point for expressing the contact end shape of the contact analysis result at a certain rotational speed using a tire finite element model by an interpolation method, and is arranged for each reference position set in a plurality of locations in the tire width direction. A plurality of reference points as one set, obtaining ground contact data based on the coordinate values of each reference point when a predetermined number of sets are provided with different rotational speeds;
Using the ground contact edge data, the coordinate values of a plurality of reference points serving as base points for calculation of the shape of the ground contact edge at a desired rotational speed are represented by coordinate values of reference points at rotational speeds other than the desired rotational speed at the respective reference positions. Calculating by approximating
Interpolating the plurality of calculated reference points to calculate a ground contact end shape at the desired rotational speed;
A computer-executable program for predicting a tire ground contact end shape.

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