JP5462125B2 - Pattern noise simulation apparatus and pattern noise simulation method - Google Patents

Description

  The present invention relates to a pattern noise simulation apparatus and a pattern noise simulation method for calculating data used for predicting pattern noise generated when contacting a road surface.

  A pneumatic tire (hereinafter referred to as a tire) mounted on a vehicle such as an automobile generates various noises. 2. Description of the Related Art Conventionally, among such noises, there has been proposed an apparatus for predicting pattern noise (specifically, pitch noise) generated when a tread portion contacts the road surface with traveling of a vehicle by simulation.

  For example, a simulation device that captures a tread portion as a two-dimensional shape and predicts pattern noise based on the shape is known (for example, Patent Document 1). There is also known a simulation apparatus that captures a tread portion as a three-dimensional shape and predicts pattern noise based on the shape (for example, Patent Document 2).

JP-A-4-148840 (columns 13-14, FIG. 3) JP 2004-85235 A (6th page, FIG. 3)

  However, the above-described conventional simulation apparatus has the following problems. That is, in the case of a simulation apparatus that captures a tread portion as a two-dimensional shape, there is a limit to predicting pattern noise generated by a tire having a complicated tread pattern in recent years with high accuracy.

  In addition, in the case of a simulation apparatus that captures a tread portion as a three-dimensional shape, the amount of calculation becomes enormous when applied to a recently complicated tread pattern.

  Therefore, an object of the present invention is to provide a pattern noise simulation apparatus and a pattern noise simulation method that can improve the prediction accuracy of pattern noise while suppressing the amount of calculation.

  A feature of the present invention is that a tread portion (tread portion 210) includes a land portion (land portion 211) that contacts the road surface (road surface R) and a groove portion (groove portion 212) that is recessed inward in the tire radial direction from the land portion. A pattern noise simulation device (simulation device 100) that calculates data used to predict pattern noise that is generated when a tire having a belt layer on the inner side in the tire radial direction from the groove portion contacts the road surface. A displacement amount calculation unit (displacement amount calculation unit 109) for calculating a displacement amount of the tread portion in the tire radial direction, wherein the displacement amount calculation unit is centered on a rotation axis (rotation axis AX) of the tire model. The amount of displacement is calculated with reference to an arcuate reference line (reference line BL), and the reference line has a groove bottom of the groove (groove bottom 212bt) and a tire than the belt layer (belt layer 230). The gist of the present invention is that the displacement amount is provided between a carcass layer positioned radially inward and the displacement is associated with the volume of pattern noise.

  In the above-described feature of the present invention, a sound pressure level determination unit that determines a sound pressure level of the pattern noise based on the displacement calculated by the displacement calculation unit may be provided.

  In the above-described feature of the present invention, the displacement amount calculation unit calculates the displacement amount in the tread portion on the stepping side, which is the side that contacts the road surface first when the tire model rolls on the road surface. Also good.

  In the feature of the present invention described above, a displacement amount display unit may be provided that displays the displacement amount in association with a predetermined color based on the displacement amount calculated by the displacement amount calculation unit.

  In the above-described feature of the present invention, a displacement portion display unit that displays a portion that is displaced in the tread portion based on the displacement amount calculated by the displacement amount calculation unit may be provided.

  According to the features of the present invention, it is possible to provide a pattern noise simulation apparatus and a pattern noise simulation method that can improve the prediction accuracy of pattern noise while suppressing the amount of calculation.

1 is a functional block diagram of a pattern noise simulation apparatus 100 according to an embodiment of the present invention. FIG. FIG. 10 is a flow chart of a pattern noise simulation operation performed by the simulation apparatus 100 according to the embodiment of the present invention. 1 is a diagram showing an example of a tire model 200 according to an embodiment of the present invention. It is a figure showing typically the amount of displacement of tire model 200 concerning an embodiment of the present invention. It is a figure for demonstrating the calculation method of the displacement amount of the reference line BL which concerns on embodiment of this invention. It is a figure which shows the example of a display of the tread part 210 by the displacement part display part 115 which concerns on embodiment of this invention. It is a figure which shows the example of a display of the displacement amount by the displacement amount display part 117 which concerns on embodiment of this invention. It is a graph which shows the relationship between the integrated value of the displacement amplitude in reference line BL (the outermost layer of the belt layer 230), and the room sound pressure level with which the tire of simulation object was mounted | worn.

  Next, an embodiment of a pattern noise simulation apparatus according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings may be contained.

(1) Functional Block Configuration of Pattern Noise Simulation Device FIG. 1 is a functional block diagram of a pattern noise simulation device 100 according to the present embodiment. The simulation apparatus 100 calculates data used for prediction of pattern noise generated when the tire model 200 (see FIGS. 3A and 3B) contacts the road surface. Specifically, the simulation apparatus 100 calculates the amount of displacement when the tread portion 210 (see FIGS. 3A and 3B) contacts the road surface.

As shown in FIG. 1, a simulation apparatus 100 includes a tire model creation unit 101, a pattern model creation unit 103, a road surface model creation unit 105, a condition setting unit 107, a displacement amount calculation unit 109, a sound pressure level determination unit 111, a sound pressure A level display unit 113, a displacement part display unit 115, and a displacement amount display unit 117 are provided.

  The tire model creation unit 101 creates a tire model 200. Further, the pattern model creation unit 103 creates a tread pattern that constitutes a part of the tire model 200.

  3A and 3B show an example of the tire model 200. FIG. As shown in FIGS. 3A and 3B, the tire model 200 includes a pattern model 200P. Further, the tire model 200 has a belt layer 230 on the inner side in the tire radial direction than the groove portion 212. Further, the tire model 200 has a carcass layer 240 located on the inner side in the tire radial direction than the belt layer 230.

  The pattern model 200P defines the shape of the tread portion 210 in which the land portion 211 and the groove portion 212 that is recessed inward in the tire radial direction from the land portion 211 are formed. The groove portion 212 is a lug groove extending along the tire width direction. The groove 212 does not necessarily have to be parallel to the tire width direction.

  The tire model 200 is used for modeling the shape, structure, and material of a tire (pneumatic tire) to be simulated. The pattern model 200P is used for detailed modeling of a tread pattern of a tire to be simulated. It is desirable that the pattern model 200P has at least twice the tire contact length under the calculation conditions.

  The tire model creation unit 101 and the pattern model creation unit 103 create one tire model 200 that reproduces a specific tread pattern by replacing a part or the whole of the tread portion 210 of the tire model 200 with the pattern model 200P.

  The road surface model creation unit 105 models a road surface R (see FIGS. 4A to 4C) corresponding to a region where the tire model 200 rolls and advances. The road surface modeled by the road surface model creation unit 105 is a plane or a curved surface. The road surface friction coefficient can be set to an arbitrary value.

  The condition setting unit 107 sets analysis conditions and boundary conditions (for example, internal pressure / load) using the road surface R modeled by the tire model 200 and the road surface model creation unit 105.

  The displacement amount calculating unit 109 displaces the tire model 200 and the pattern model 200P when the tire model 200 and the pattern model 200P are rolled while making a part of the tire model 200 (specifically, the pattern model 200P) contact the modeled road surface R. Is calculated.

  Specifically, the displacement amount calculation unit 109 calculates the displacement amount in the tire radial direction of the tread portion 210 when a part of the tire model 200 (specifically, the pattern model 200P) is rolled while being in contact with the tire model 200. To do.

  Here, FIGS. 4A to 4C schematically show the displacement amount of the tire model 200. FIG. The displacement amount calculation unit 109 is in the tire radial direction of the tread portion 210 (specifically, the Z direction in FIG. 4A) with the arc-shaped reference line BL centered on the rotation axis AX of the tire model 200 as a reference. Calculate the displacement.

  When the land portion 211 contacts the road surface R, the tire model 200 is displaced inward in the tire radial direction. Further, when the tire model 200 rolls, the land portion 211 displaced toward the inside in the tire radial direction, specifically, the tread portion 210 near the ground contact end including the groove bottom 212bt of the groove portion 212 faces the outside in the tire radial direction. To displace. The tire model 200 repeats the displacement in the tire radial direction of the land portion 211, specifically, the tread portion 210 near the ground contact end including the groove bottom 212bt of the groove portion 212. The displacement amount calculation unit 109 calculates such a displacement amount of the tread portion 210.

  Further, when comparing the land portion 211 and the groove portion 212, the displacement amount of the groove portion 212 where the rubber block forming the land portion 211 is not present is larger than the displacement amount of the land portion 211. That is, the groove portion 212 causes repeated displacement in the tire radial direction. Although the displacement amount of the groove portion 212 is larger than the displacement amount of the land portion 211, the deformation in the tire radial direction does not occur only in the land portion 211.

  In the present embodiment, the reference line BL is provided between the groove bottom 212bt of the groove 212 and the outermost layer of the belt layer 230. Note that the reference line BL is preferably at a position overlapping the outermost layer of the belt layer 230 from the viewpoint of highly accurate measurement (prediction) of the displacement amount. In addition, the reference line BL may be provided between the groove bottom 212bt and the carcass layer 240.

  Further, it is preferable that the displacement amount calculation unit 109 calculates the displacement amount in the tread portion 210 on the stepping side that is the side that comes in contact with the road surface R first when the tire model 200 rolls on the road surface R.

  In particular, when calculating the displacement amount on the shoulder side of the tread portion 210, a highly accurate simulation can be realized by calculating the displacement amount on the tread portion 210 on the stepping side. On the other hand, when calculating the displacement amount on the center side of the tread portion 210, it is not necessarily limited to the stepping side, and it is also possible to calculate the displacement amount in the tread portion 210 on the kick-out side, which is the side away from the road surface R. Highly accurate simulation can be realized. The exact measurement (prediction) position of the displacement amount depends on the size of the tire model 200 (tire), but in the case of a tire for a general passenger car, the ground between the tread portion 210 and the road surface R The position is preferably about 30 mm away from the end. Further, it is more preferable to set the integrated value of the displacement amount to a position 30 mm away from the ground contact end.

  The displacement amount calculation unit 109 calculates the deformation trajectory of the curved surface (arc surface) along the tread portion 210 based on the above-described calculation result of the displacement amount of the tread portion 210, and calculates the displacement amount at each position of the tread portion 210. Calculate the size. A specific method for calculating the deformation trajectory of the tread portion 210 will be described later.

  The sound pressure level determination unit 111 determines the sound pressure level of the pattern noise based on the displacement amount calculated by the displacement amount calculation unit 109. Specifically, the sound pressure level determination unit 111 performs pattern noise detection based on a table in which the amount of displacement and the vehicle interior sound pressure level (unit: dBA) are associated with each other, or a mathematical expression representing the corresponding relationship. Determine the sound pressure level. Note that the sound pressure level determination unit 111 may target not only the sound pressure level outside the vehicle but also the room sound pressure level of the vehicle by changing a table or a mathematical formula to be used.

  The sound pressure level display unit 113 displays the sound pressure level determined by the sound pressure level determination unit 111. That is, the sound pressure level display unit 113 displays the sound pressure level of the pattern noise (pitch noise) predicted to be generated when the tire targeted for simulation rolls on the road surface.

  The displacement portion display unit 115 displays a portion that is displaced in the tread portion 210 based on the displacement amount calculated by the displacement amount calculation unit 109. FIG. 6 shows a display example of the tread portion 210 by the displacement portion display portion 115.

  As shown in FIG. 6, a portion with a large displacement (displacement in the z direction: unit mm) is displayed in a dark color, and a portion with a small displacement is displayed in a light color. “Center” and “shoulder” indicate the center side and the shoulder side of the tread portion 210, respectively. “Fumi” and “Keri” indicate the stepping side and the kicking side of the tread portion 210, respectively. Further, the displacement part display unit 115 displays how each part of the tread part 210 is displaced over time.

  Based on the displacement amount calculated by the displacement amount calculation unit 109, the displacement amount display unit 117 displays the magnitude of the displacement amount in association with a predetermined color. That is, the sound pressure level display unit 113 visualizes the magnitude of the displacement amount with the color distribution. FIG. 7 shows a display example of the displacement amount by the displacement amount display unit 117.

  As shown in FIG. 7, a portion with a large amount of displacement (specifically amplitude) is displayed in a dark color, and a portion with a small amount of displacement is displayed in a light color. As shown in FIG. 7, according to the display example by the displacement amount display unit 117, it is clear that the displacement amount in the vicinity of the ground contact end on the stepping side and the kicking side is extremely large.

(2) Pattern Noise Simulation Method FIG. 2 shows a flow of pattern noise simulation operation by the simulation apparatus 100 described above.

  As shown in FIG. 2, in step S10, the simulation apparatus 100 sets a design plan for a tire to be simulated. The design plan includes the shape, structure, material, tread pattern, and the like of the tire model 200.

  In steps S20 to S40, the simulation apparatus 100 creates a tire model 200, a road surface R model, and a pattern model 200P. Note that the method of creating these models is the same as that of a conventional simulation apparatus (for example, JP-A-2004-85235).

  In step S50, the simulation apparatus 100 sets analysis conditions and boundary conditions (for example, internal pressure / load) using the tire model 200 and the modeled road surface R.

  In step S60, the simulation apparatus 100 analyzes the rolling state of the tire model 200 having a tread pattern (pattern model 200P). Specifically, as described above, the simulation apparatus 100 calculates the amount of displacement of the tread portion 210 in the tire radial direction based on the reference line BL (see FIGS. 4B and 4C).

  In step S70, the simulation apparatus 100 calculates a deformation trajectory of the curved surface (arc surface) along the tread portion 210.

  Here, FIGS. 5A to 5D are diagrams for explaining a calculation method of the displacement amount of the curved surface (arc surface) along the tread portion 210, that is, the reference line BL. As shown in FIG. 5 (a), the simulation apparatus 100 calculates the displacement amount of each part of the tire model 200 in the coordinate system (x, y, z) with the rotation axis AX as a reference. Since the coordinate positions of are completely different, it is impossible to calculate the deformation as relative coordinates from the tire center.

  Therefore, as shown in FIGS. 5B1 and 5B2, the displacement amount is approximated to a preset grid for each calculation step. The grid coordinate system may be arbitrary. For example, the x and y grids may be fixed and the z coordinates may be compared. Alternatively, the R coordinate may be compared with a zθ grid fixed as a cylindrical coordinate system. In the figure, two-dimensionally displayed for easy understanding, but the processing is actually executed in three dimensions.

  By such a process, as shown in FIG. 5C, the change from Step N to Step N + 1 can be expressed as the amount of displacement of the tire in the coordinate system fixed to the tire center.

  In step S80, the simulation apparatus 100 extracts a displacement amount on the curved surface along the tread portion 210. FIG. 5D shows an example of extraction of the displacement amount at the z coordinate extracted by the simulation apparatus 100.

  In step S90, the simulation apparatus 100 displays the sound pressure level associated with the extracted displacement amount, and evaluates the simulation result.

  In step S100, the simulation apparatus 100 causes the designer to determine whether or not the performance of the tire model 200 to be simulated is good as a result of the simulation.

  If the performance reaches the acceptance standard and is good, the design plan is adopted in step S110. On the other hand, if the performance does not reach the acceptance standard, the designer corrects the design plan in step S120.

  In step S130, the simulation apparatus 100 visualizes the amount of displacement on the curved surface along the tread portion 210 (see FIGS. 6 and 7 described above).

(3) Action / Effect FIG. 8 is a graph showing the relationship between the integrated value of the displacement amplitude in the reference line BL (the outermost layer of the belt layer 230) and the room sound pressure level where the simulation target tire is mounted. The data shown in the graph of FIG. 8 is measured under the following conditions.

・ Tire size: 195 / 65R15 tires ・ Applicable rim size: 6J-15
・ Set internal pressure: 180kPa
・ Set load: 4.52kN
・ Setting speed: 80km / h
・ Test method: Roll the tire with an indoor drum tester and measure the sound pressure using a microphone on the side of the tire, as shown in FIG. There is a clear correlation between. That is, it can be understood that the pattern noise can be predicted with high accuracy by performing a simulation on the displacement amount of the reference line BL in the tire radial direction.

  That is, according to the simulation apparatus 100, it is possible to predict the pattern noise (pitch noise) with high accuracy by calculating the displacement amount in the tire radial direction of the tread portion 210 with reference to the reference line BL.

  In addition, such a calculation method does not require an enormous amount of calculation unlike a conventional simulation device that captures a tread portion as a three-dimensional shape (a simulation device that uses both deformation calculation and acoustic calculation). Furthermore, since only the displacement amount of the tread portion 210 in the tire radial direction is calculated, it is possible to flexibly cope with a tire having a complicated tread pattern in recent years.

  For this reason, the simulation apparatus 100 is effective in predicting the noise performance of the tire design plan. By utilizing the simulation apparatus 100, the improvement without the trial production of the tire can be promoted, the efficiency of the tire development and the tire performance ( Contributes to improvement of (silence).

  Moreover, in this embodiment, since the said displacement amount and a displacement part are visualized, evaluation of the tire made into the object of simulation becomes easy.

(4) Other Embodiments As described above, the contents of the present invention have been disclosed through the embodiments of the present invention. However, it is understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. Should not. From this disclosure, various alternative embodiments, examples, and operational techniques will be apparent to those skilled in the art.

  For example, in the embodiment described above, the displacement amount and the sound pressure level extracted by the simulation apparatus 100 are associated, but the association is performed directly by another computer or operator, not the simulation apparatus 100. It doesn't matter.

  Further, the pattern noise may be other values (for example, a vehicle exterior noise level (measured value using an actual vehicle)) instead of the room sound pressure level.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is determined only by the invention specifying matters according to the scope of claims reasonable from the above description.

100 ... Simulation equipment
200 ... tire model
200P ... Pattern model
210 ... tread
211 ... Land
212 ... Groove
212bt ... groove bottom
230 ... Belt layer
240 ... Carcass layer
AX ... Rotation axis
BL ... Reference line
R ... road surface

Claims (6)

A tire model having a belt layer on the inner side in the tire radial direction with respect to the road surface is formed on the road surface. A pattern noise simulation device for calculating data used for prediction of pattern noise generated when
A displacement amount calculating section for calculating a displacement amount in the tire radial direction of the tread portion;
The displacement amount calculation unit calculates the displacement amount with reference to an arc-shaped reference line centered on the rotation axis of the tire model,
The reference line is provided between a groove bottom of the groove and a carcass layer located on the inner side in the tire radial direction from the belt layer,
The displacement amount is a pattern noise simulation device associated with the volume of the pattern noise.   The pattern noise simulation device according to claim 1, further comprising: a sound pressure level determination unit that determines a sound pressure level of the pattern noise based on the displacement amount calculated by the displacement amount calculation unit.   3. The displacement amount calculation unit according to claim 1, wherein when the tire model rolls on the road surface, the displacement amount calculation unit calculates the displacement amount in a tread portion on a stepping side that is a side that comes into contact with the road surface first. Pattern noise simulation device.   4. The displacement amount display unit according to claim 1, further comprising a displacement amount display unit configured to display the displacement amount in association with a predetermined color based on the displacement amount calculated by the displacement amount calculation unit. Pattern noise simulation device.   5. The pattern noise simulation device according to claim 1, further comprising a displacement portion display unit that displays a portion that is displaced in the tread portion based on the displacement amount calculated by the displacement amount calculation unit. . A tire model having a belt layer on the inner side in the tire radial direction with respect to the road surface is formed on the road surface. A pattern noise simulation method for calculating data used to predict pattern noise that occurs when
Calculating a displacement amount of the tread portion in the tire radial direction;
Determining a sound pressure level of the pattern noise based on the calculated amount of displacement,
In the step of calculating the displacement amount, the displacement amount is calculated with reference to an arc-shaped reference line centered on the rotation axis of the tire model,
The reference line is provided between the groove bottom of the groove and the outermost layer of the belt layer,
The displacement amount is a pattern noise simulation method associated with the volume of pattern noise.