JP5467027B2 - Tire wear test apparatus, method, and program - Google Patents

Description

  The present invention relates to a tire wear test apparatus, method, and program.

  Conventionally, as a method of measuring the load on a tire mounted on a car, a method of measuring by attaching a force meter to a wheel on which the tire is mounted, or embedding a force meter on the road surface and passing the tire on it However, it took a lot of labor and expense to install and process the force meter, which was inefficient.

  For example, Patent Document 1 discloses a method for estimating a load on a tire using a vehicle model using a computer in combination with a biaxial acceleration of a longitudinal acceleration and a lateral acceleration.

  Further, in Patent Document 2, based on a road profile simulation, a vehicle wheel is rotated while applying a displacement of up to six axes to each wheel of the vehicle, or resistance is applied to the rotation of the wheel, thereby A method for enabling dynamic simulation is disclosed.

  In Patent Document 3, a spindle shaft provided with a rim and rotatably supported, and a drum rotating body rotatable around a drum shaft parallel to the spindle shaft, a tire is mounted on the rim. In the tire test method for measuring the characteristics of the tire by rotating the tire rotating body by bringing the tire rotating body into contact with the drum rotating body and applying a rotational force to one of the rotating bodies, The rotational acceleration of the tire rotating body and the fluctuation component of the longitudinal force acting on the tire of the tire rotating body are obtained, and based on the rotational acceleration, the longitudinal force is generated by vibration caused by the rotation of both rotating bodies. A tire test method is disclosed in which a vibration component included in the fluctuation component is calculated and correction is performed to remove the vibration component from the fluctuation component of the longitudinal force.

  Further, Patent Document 4 discloses a wear amount per predetermined travel distance of the tire when the tire is worn in a state where a predetermined input having a predetermined size is applied to a tire whose wear life is to be predicted by a drum wear test. And determining the first frictional energy of the tire in a state where the same input as that applied to the tire in the drum wear test is applied at the same or substantially the same size as the predetermined size, A second friction energy of the tire in a state where an input taking into account an input at the time of traveling is given is obtained, and a wear index indicating the ease of wear of the tire is calculated based on the wear amount and the first friction energy. A tire wear life prediction method for predicting the wear life of the tire based on the wear index and the second friction energy is disclosed.

JP 2007-139708 A JP 2005-525549 Gazette JP 2008-58082 A JP 2003-50190 A

  In an actual vehicle, even if the acceleration is small, a large lateral deformation may occur due to vehicle characteristics when the turning radius of the vehicle is small.

  Even if the acceleration in the lateral direction is the same, the radius of rotation decreases as the speed decreases, and in the case of a general four-wheeled vehicle, the ground angle of the tire (ground slip angle) changes between the left and right wheels. This phenomenon is generally referred to as the influence of Ackermann, but as a load applied to the tire, it can sufficiently affect durability and wear performance. This indicates that when the speed is low, the rotational radius is small and a lateral force larger than the lateral force (load × lateral acceleration) obtained only from the lateral acceleration is applied.

  For example, even if the average speed is 60 km / h, if there is a traveling section with a speed of 160 km / h during traveling, the wear in the traveling section with a high air resistance of 160 km / h occupies most, and the average speed is simply reduced. The amount of wear increases as compared with the case where the amount of wear is tested.

  On the other hand, conventionally, only the longitudinal acceleration and lateral acceleration of the tire are considered, so the influence of the turning radius of the vehicle is not accurately reflected in the lateral deformation and lateral force of the tire, and the tire There was a problem that the amount of wear could not be accurately tested.

  An object of the present invention is to obtain a tire wear test apparatus, method, and program capable of accurately testing a tire wear amount in consideration of the above facts.

  In order to achieve the above object, the tire wear test apparatus according to the first aspect of the present invention is an acquisition means for acquiring acceleration and speed data measured every predetermined time when the vehicle travels on a predetermined test course. Lateral force calculation means for calculating longitudinal force and lateral force generated in the vehicle based on the acceleration acquired by the acquisition means and a load predetermined based on the vehicle, and the lateral direction acquired by the acquisition means A turning radius calculating means for calculating a turning radius of the vehicle based on the acceleration and speed of the vehicle, the turning radius calculated by the turning radius calculating means, a distance between tires of a front wheel of the vehicle, and a front wheel of the vehicle; Tire angle calculating means for calculating the tire angles of the left and right front wheels of the vehicle based on the inter-axis distance with the rear wheel, the lateral force calculated by the lateral force calculating means, and the tie Based on the angle difference between the tire angles of the left and right front wheels calculated by the angle calculation means and a predetermined angle difference between the tire angles of the left and right front wheels when the vehicle is not running, the lateral force An output for outputting tire wear test data including an increment calculating means for calculating an increment, the longitudinal force and the lateral force calculated by the calculating means, and the increment of the lateral force calculated by the increment calculating means. Means.

  According to this invention, not only the longitudinal force and lateral force obtained from the longitudinal acceleration and lateral acceleration, but also the turning radius is obtained from the lateral acceleration and velocity, and the increment of the lateral force is calculated from the obtained turning radius. Calculate and output as tire wear test data. The output means outputs the wear test data to the storage means and stores it, or outputs it to the wear test machine to perform the wear test.

  In the wear test, wear test data output by the output means is used. Thereby, since the increment of the lateral force is applied to the tire as a load, the wear amount can be accurately tested as compared with the case where only the longitudinal force and the lateral force are applied to the tire as in the conventional case.

  According to a second aspect of the present invention, it is preferable that the output means outputs an acceleration in the vertical direction of the vehicle acquired by the acquisition means included in the tire wear test data.

  Thereby, the fluctuation of the load in the vertical direction of the vehicle is taken into consideration, and the wear amount can be tested with higher accuracy.

  According to a third aspect of the present invention, it is possible to include a wear test means for testing the amount of tire wear based on the tire wear test data.

  And as described in Claim 4, it is preferable that the said abrasion test means tests the abrasion amount of the said tire about each of the tire on the right and left of the front wheel of the said vehicle.

  As a result, it is possible to accurately test the wear amount of the left and right tires of the front wheels.

  According to a fifth aspect of the present invention, there is provided a tire wear test method comprising: acquiring acceleration and speed data measured every predetermined time when the vehicle travels on a predetermined test course; and acquiring the acceleration and the vehicle Calculating a longitudinal force and a lateral force generated in the vehicle based on a predetermined load, calculating a turning radius of the vehicle based on the acquired lateral acceleration and speed, and calculating Calculating the tire angles of the left and right front wheels of the vehicle based on the turning radius, the inter-tire distance of the front wheel of the vehicle, and the inter-axis distance between the front and rear wheels of the vehicle; Based on the calculated lateral force, the calculated angle difference between the tire angles of the left and right front wheels, and the predetermined angle difference between the tire angles of the left and right front wheels when the vehicle is not running. Calculating a lateral force increment; and outputting tire wear test data including the calculated longitudinal force and lateral force, and the calculated lateral force increment. And

  A tire wear test program according to a sixth aspect of the present invention is a tire wear program for causing a computer to function as each means constituting the tire wear test apparatus according to any one of the first to fourth aspects. It is a test program.

  According to the present invention, there is an effect that the amount of wear of a tire can be accurately tested.

It is the schematic of the personal computer for implementing performance prediction of a tire. It is a schematic block diagram of a computer. 3 is a flowchart of a tire wear test program. It is the diagram which showed the relationship between the load concerning a tire, and lateral force. It is the diagram which showed the relationship between the load concerning a tire, and a camber angle. It is a figure which shows the relationship of the acceleration of an up-down direction, a load, a lateral force, and a camber angle | corner at the time of a vehicle drive | working the driving | running | working course. It is a figure for demonstrating the angle of the tire on either side of the front wheel of a vehicle. It is the diagram which showed the relationship between the turning radius of a tire, and lateral force. It is a diagram which shows the abrasion loss of each part of the tire width direction by an abrasion test. It is a diagram which shows the abrasion loss of each part of the tire width direction by a real vehicle.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an outline of a personal computer as a tire wear test device for generating pneumatic tire wear test data as an example and testing the amount of tire wear based on the generated wear test data. ing. The personal computer includes a keyboard 10 for inputting data and the like, a computer 12 for executing a tire wear test according to a pre-stored processing program, a display 14 for displaying calculation results and various screens by the computer 12, and a display 14 The mouse 16 is configured to move the cursor displayed at the desired position, and to select, deselect, or drag the menu item or object at the cursor position.

  As shown in FIG. 2, the computer 12 includes a CPU (Central Processing Unit) 12A, a ROM (Read Only Memory) 12B, a RAM (Random Access Memory) 12C, a non-volatile memory 12D, and an input / output interface (I / O) 12E. Are connected to each other via a bus 12F.

  Connected to the I / O 12E are a keyboard 10, a display 14, a mouse 16, a hard disk 18, a CD-ROM drive 21 into which a CD-ROM 20 as a recording medium can be inserted and removed, and a wear test unit 22.

  The hard disk 18 contains data necessary for a tire wear test program and a wear test, which will be described later, and data necessary for acceleration and speed measured when the test course is run, and other tire wear test programs. Various parameters and data are stored. The CPU 12A reads and executes a tire wear test program stored in the hard disk 18.

  Note that a tire wear test program, which will be described later, can be read from the CD-ROM 20 using, for example, the CD-ROM drive 21, and therefore a tire wear test program, which will be described later, is recorded in the CD-ROM 20 in advance. The tire wear test program recorded on the CD-ROM 20 via the CD-ROM drive 21 may be read and executed.

  Further, the recording medium is not limited to the CD-ROM, but includes an optical disk such as a DVD-ROM and a magneto-optical disk such as MD and MO. When these are used, the CD-ROM drive 21 is replaced with a DVD-ROM. A ROM drive, MD drive, MO drive or the like may be used.

  The wear test unit 22 tests the amount of wear of a tire by applying a longitudinal force, a lateral force, etc. to the set tire and rotating the tire based on the input tire wear test data. It consists of a drum testing machine.

  Next, as a function of the present embodiment, a processing routine of a tire wear test program executed by the computer 12 will be described with reference to a flowchart shown in FIG.

  Before executing this program, attach a 3-axis accelerometer and a speedometer to the vehicle and run on a predetermined test course, and set the vehicle's longitudinal acceleration, lateral acceleration, vertical acceleration, and speed for a predetermined time. Measure and acquire every time. This measurement data is predetermined and stored in the hard disk 18, for example.

  FIG. 4 shows an example of the relationship between the load applied to the vehicle and the lateral force, and FIG. 5 shows an example of the relationship between the load and the camber angle. From such a relationship, as shown in FIG. 6, when the vehicle 24 travels on a test course 26 that goes up a hill as an example, the vertical acceleration, load, and lateral force are large on the uphill 26 </ b> A. Thus, the camber angle becomes small. In addition, at the top 26 </ b> B that starts to climb and descend, the vertical acceleration, load, and lateral force are reduced, and the camber angle is increased. On the downhill 26C, the vertical acceleration, load, and lateral force increase, and the camber angle decreases.

  As described above, since the acceleration in the vertical direction affects the load, the lateral force, and the camber angle, in the present embodiment, the acceleration in the vertical direction is taken into consideration when generating the wear test data.

  In step 100, the acceleration and velocity measurement data in each direction stored in the hard disk 18 are read.

  In step 102, longitudinal force and lateral force are calculated for each time based on the read acceleration and load at each time, and stored in the hard disk 18. At this time, the load is set to a predetermined value based on the vehicle information of the vehicle that has traveled the test course. The longitudinal force is calculated by multiplying the longitudinal acceleration by the load, and the lateral force is obtained by multiplying the lateral acceleration by the load.

  In step 104, the turning radius R of the vehicle is calculated for each time. The turning radius R can be calculated by the following equation, where V is the speed and Gy is the lateral acceleration.

R = V ² / Gy (1)

In step 106, the angles θ _R and θ _L of the left and right tires of the front wheels of the vehicle are calculated for each time. As shown in FIG. 7, assuming that the distance between the left and right tires of the front wheels is W and the distance between the front wheels and the rear wheels is _L, the following equations are established for θ _R and θ _L when turning left.

θ _R = tan ⁻¹ [{L / (R ² −L ² )} ^1/2 + W / 2] (2)

θ _L = tan ⁻¹ [{L / (R ² −L ² )} ^1/2 −W / 2] (3)

  Further, when turning right, the following equation holds.

θ _R = tan ⁻¹ [{L / (R ² −L ² )} ^1/2 −W / 2] (4)

θ _L = tan ⁻¹ [{L / (R ² −L ² )} ^1/2 + W / 2] (5)

  In the present embodiment, it is not necessary to determine whether the vehicle is turning right or left from an expression for obtaining an increase in lateral force, which will be described later, and it is only necessary to calculate two different angles. , (2), two different angles may be calculated.

  In step 108, the increment of the lateral force generated in the left and right tires of the front wheels of the vehicle is calculated for each time.

_{F R = cp × (| θ} R -θ L | - | θ R '-θ L' |) / 2 ··· (6)

_{F L = -cp × (| θ} R -θ L | - | θ R '-θ L' |) / 2 ··· (7)

Here, cp is a cornering force of the tire, that is, a lateral force generated according to the angle of the tire, and the lateral force obtained in step 102. Also, | θ _R '−θ _L ' | is the angle difference between the left and right tires when the vehicle is just turning without traveling, that is, the angle difference between the left and right tires when the tire is stationary.

Incremental _F R of the lateral force of each time calculated, _{F L} is stored in the hard disk 18. As shown in FIG. 8, the relationship between the turning radius R and the lateral force is such that the lateral force increases as the turning radius R decreases. Therefore, it is important to consider the turning radius in the tire wear test.

  In step 110, the vertical acceleration at each time of the measurement data stored in the hard disk 18, the longitudinal and lateral forces at each time stored in the hard disk 18 in step 102 in step 100, and stored in the hard disk 18 in step 108. Each data of the increment of lateral force at each time is output to the wear test unit 22 as tire wear test data, and the amount of tire wear is tested.

  The wear test unit 22 applies the input tire test data, that is, acceleration in the vertical direction, longitudinal force, lateral force, and lateral force to the set tire to rotate and test the amount of wear. To do. This test is performed on both the left and right tires of the front wheels of the vehicle. Thereby, it is possible to accurately test the amount of wear of each of the left and right tires of the front wheel.

  As described above, in this embodiment, not only the longitudinal force and lateral force obtained from the longitudinal acceleration and lateral acceleration, but also the turning radius is obtained from the lateral acceleration and velocity, and the lateral force is obtained from the obtained turning radius. Calculate the increment. In the wear test, load fluctuation due to acceleration in the vertical direction is applied to the tire as the lateral force increases, so the accuracy is higher than in the conventional case where only the longitudinal force and lateral force are applied to the tire. The wear amount can be well tested. Note that the wear test may be performed by omitting the vertical acceleration.

  In the present embodiment, a case where the wear test is performed by the wear test unit 22 configured by a drum testing machine or the like has been described. However, the present invention is not limited thereto, and the tire wear amount is simulated based on the tire wear test data. It may be. In other words, a tire model based on the finite element method is created, and the amount of tire wear is determined by rolling analysis by adding incremental acceleration, longitudinal force, lateral force, and lateral force to the created tire model. You may make it simulate. In this case, the wear test part 22 can be omitted.

  In addition, when observing the ground contact shape of a tire with a road surface observation device, the acceleration of the vertical direction, longitudinal force, lateral force and lateral force are applied to the tire based on the tire wear test data. Then, the ground contact shape of the tire may be observed.

  (Example)

  Next, examples of the present invention will be described.

  FIG. 9 shows the test results of the amount of wear of each part of the tire when the test target tire is set on a drum testing machine to which an actual road surface imitating an actual road surface is pasted and is run for 5000 km. It was. Note that the drum testing machine can apply a longitudinal force, a lateral force, a load, and a camber angle to the tire.

  FIG. 10 shows the result of measuring the amount of tire wear by running the test course in an actual vehicle.

  In FIG. 9, “No consideration” calculates the longitudinal force and lateral force of the tire using only the longitudinal and lateral accelerations among the accelerations in the respective directions acquired when the vehicle traveled on the test course, The result when the amount of wear is tested by applying the calculated longitudinal force and lateral force to the tire and rotating the tire is shown.

  In addition to the case of “no consideration”, “Ackermann” tested the amount of wear by loading the tire with the increment of the lateral force obtained from the turning radius obtained from the lateral acceleration and speed as described above. Shows the results of the case.

  In addition to “no consideration”, “load fluctuation” indicates a result when the amount of wear is tested by applying a load to the tire while changing the load from the vertical acceleration.

  Further, “both considerations” show results when the amount of wear was tested by applying both lateral force increments and load fluctuations to the tire in consideration of both “Ackermann” and “load fluctuations”.

  As shown in FIG. 9, in the case of “Ackerman”, the amount of wear on the shoulder portion on the outer side in the tire width direction is particularly large. This is because the increase in lateral force when the turning radius is small promotes wear.

  Further, in the case of “considering both”, the wear amount of both the outer and inner shoulder portions in the tire width direction is increased. This indicates that the load fluctuation due to the acceleration in the vertical direction has a great influence.

  From the above, compared with the case of “no consideration” in which both the turning radius and the load fluctuation due to the vertical acceleration are not taken into account, the “Ackermann” in consideration of the turning radius is more in the actual vehicle wear amount shown in FIG. Nearly, in the case of “both consideration” considering the load fluctuation due to the vertical acceleration in addition to the turning radius, it is found that the wear amount of the actual vehicle is closer, and the present invention is effective in predicting the wear amount of the tire. I found out.

10 Keyboard 12 Computer 14 Display 16 Mouse 18 Hard Disk 21 CD-ROM Drive 22 Abrasion Test Section

Claims (6)

Acquisition means for acquiring acceleration and speed data measured every predetermined time when the vehicle travels on a predetermined test course;
Lateral force calculation means for calculating longitudinal force and lateral force generated in the vehicle based on the acceleration acquired by the acquisition means and a predetermined load based on the vehicle;
A turning radius calculating means for calculating a turning radius of the vehicle based on the lateral acceleration and speed acquired by the acquiring means;
The tire angles of the left and right front wheels of the vehicle based on the turning radius calculated by the turning radius calculating means, the distance between the tires of the front wheels of the vehicle, and the distance between the axles of the front and rear wheels of the vehicle. Tire angle calculating means for calculating
The lateral force calculated by the lateral force calculating means, the angular difference between the tire angles of the left and right front wheels calculated by the tire angle calculating means, and the tire angles of the left and right front wheels when the vehicle is not running. An increment calculating means for calculating an increment of the lateral force based on a predetermined angle difference;
Output means for outputting tire wear test data including the longitudinal force and the lateral force calculated by the calculating means, and the increment of the lateral force calculated by the increment calculating means;
Tire wear test equipment including. The tire wear test apparatus according to claim 1, wherein the output means outputs the acceleration in the vertical direction of the vehicle acquired by the acquisition means in the tire wear test data. The tire wear test apparatus according to claim 1 or 2, further comprising: a wear test means for testing a tire wear amount based on the tire wear test data. The tire wear test apparatus according to claim 3, wherein the wear test means tests the amount of wear of the tire for each of the left and right tires of the front wheel of the vehicle. Acquiring acceleration and speed data measured every predetermined time when the vehicle travels on a predetermined test course;
Calculating a longitudinal force and a lateral force generated in the vehicle based on the acquired acceleration and a predetermined load based on the vehicle;
Calculating a turning radius of the vehicle based on the acquired lateral acceleration and speed;
Calculating tire angles of left and right front wheels of the vehicle based on the calculated turning radius, a distance between tires of a front wheel of the vehicle, and an inter-axis distance between a front wheel and a rear wheel of the vehicle;
Based on the calculated lateral force, the calculated angular difference between the tire angles of the left and right front wheels, and the predetermined angular difference between the tire angles of the left and right front wheels when the vehicle is not running, Calculating a lateral force increment;
Outputting tire wear test data including the calculated longitudinal force and lateral force, and the calculated increment of lateral force;
A tire wear test method including:   The tire wear test program for functioning a computer as each means which comprises the tire wear test apparatus of any one of Claims 1-4.

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