JP2010019563A - Method for testing vehicle handling stability - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle handling stability test method for evaluating the handling stability of a vehicle quantitatively. <P>SOLUTION: In this method, the vehicle is made to travel on a fixed course at a prescribed speed, and handling stability performances of the vehicle are compared and evaluated. On that occasion, steering angles of its steering wheel are measured at fixed time intervals, and the handling stability is evaluated to be more excellent as the average value of steering angular velocities (St steering angular velocities) of the steering wheel is smaller. There is a correlation between the average value of the steering angular velocities of the steering wheel and the steering stability which can be evaluated by a cornering change tendency (F change tendency). Accordingly, the steering stability is evaluated quantitatively. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle handling stability test method, and more particularly to a vehicle handling stability test method that is most suitable for performing a high-speed running test with a pneumatic tire attached thereto.

  In the development of pneumatic tires, it is important to evaluate the performance of the developed tires. In performing this performance evaluation, not only the performance evaluation is performed by rotating the tire in the bench test, but it is conventionally performed that the developed tire is mounted on the vehicle and evaluated by running on a predetermined course. Yes.

  By the way, when evaluating the steering stability performance by running the vehicle as described above, the tire developer can feel the change of the vehicle and experience the change of the vehicle, so the tire developer can experience the change of the vehicle with respect to the steering. The percentage of reliance on driver sensory evaluation was high.

As a countermeasure, Patent Document 1 discloses that measurement data and a moving image obtained by capturing tire behavior are quantitatively linked.
However, it has not yet reached a sufficient quantitative evaluation of vehicle handling stability.
JP 2002-206992 A

  In view of the above fact, an object of the present invention is to provide a vehicle handling stability test method for quantitatively evaluating the handling stability of a vehicle.

The present inventor conducted interviews with general users and test drivers in order to define the steering stability (controllability) of the vehicle, and in the following cases a) and b), the controllability is good, that is, the steering stability. Defined as good.
a) The characteristic change after the grip limit occurs gently and the change margin is small.
b) The movement state where the vehicle is placed can be easily maintained with little correction steering.

  In order to quantify this definition, paying attention to the steering amount (St steering amount), further experiments and examinations are conducted, and a correlation is derived that the steering stability of the vehicle is good if the average value of the steering steering angular velocity is small, The present invention has been completed.

  The invention according to claim 1 is a vehicle steering stability test method in which a vehicle is driven on a predetermined course at a specified speed and the steering stability performance of the vehicle is compared and evaluated, and the steering angle of the steering wheel is constant. It is measured every hour, and it is assumed that the steering stability is better as the average value of the steering angular velocity of the steering wheel is smaller.

  There is a correlation between the average value of the steering wheel angular velocity and the steering stability. Therefore, according to the invention described in claim 1, the steering stability can be quantitatively evaluated.

The invention according to claim 2 is a course including a continuous corner in which the certain course needs to turn the steering wheel back and forth.
Thereby, the steering stability of the vehicle can be more accurately evaluated.

  According to a third aspect of the present invention, the predetermined time is 0.02 second or more and shorter than 0.1 second, and an average value of the steering angular velocity of the steering wheel is calculated as the steering angle of the steering wheel at the predetermined time. Is obtained by dividing the total amount of change by the time traveled on the predetermined course.

  If the fixed time is shorter than 0.02 seconds (1/50 Hz), the apparatus becomes large. Moreover, when it is 0.1 second (10 Hz) or more, the measurement interval becomes too long when the speed of the vehicle is high. In addition, if it measures so that the said fixed time may become a period of 10-30 Hz, it will be easy to measure the steering angular velocity of a steering wheel correctly.

  According to the third aspect of the present invention, the steering stability of the vehicle can be more accurately evaluated by simple data processing.

The invention according to claim 4 is comparatively evaluated by changing the tire type to be mounted on the vehicle.
The tire type is not particularly limited.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the vehicle steering stability test method which evaluates steering stability quantitatively.

  Hereinafter, embodiments will be described and embodiments of the present invention will be described. As shown in FIGS. 1 and 2, in one embodiment of the present invention, a steering angle meter 12 that measures a steering angle of a steering wheel by fixing an angular scaled disk 10 to a boss portion of a steering wheel of a vehicle. Attach (for example, made by Mutek).

  In the present embodiment, the vehicle is driven at a specified speed on a certain course. When traveling, the steering angle meter 12 measures the steering angle θ (St steering angle) of the steering wheel 14 at regular intervals (for example, measured every 0.05 seconds, that is, at 20 Hz), as shown in FIG. The measured St steering angle is transmitted as an electric signal. The transmitted electrical signal is subjected to data processing by the following method and calculated as the St steering angle.

Amp. Is used, it is converted into data for Excel using analysis software “μ-Logger” manufactured by Mutech. When using VBOX made by RaceLogic, it is converted into data for Excel using analysis software “VBOX” made by RaceLogic. In any case, the total steering angle, that is, the St steering angle is calculated on Excel, and an average value of steering angular velocities (refer to the description below) of the steering wheel is obtained. There is a correlation between the average value of the St steering angular velocity and the steering stability, and it is determined that the steering stability is better as the average value is smaller.
Thereby, it is possible to quantitatively evaluate the steering stability of the vehicle to which the tire to be tested is attached.

<Test example>
In this test example, as shown in FIG. 4, a test course 20 having a large bend like a circuit was used and the test was performed in actual vehicle running. This test course 20 is formed with an S-shaped road, and the steering angle of the steering wheel becomes large and the vehicle runs marginally at a continuous corner that turns back to the left or right, or a composite corner that goes back and forth in the middle. It is a possible course. In this test example, the curves 22 and 24 are both arcs of 60R (radius 60m).

As a load condition, a load of 7.50 kN was applied to the tire on the front side during traveling. The speed condition on the test course 20 was to enter at a speed of 80 km / h, to accelerate slowly and to escape at 100 km / h.
In the past, a load of 4.66 kN was statically applied to the front tire, and an indoor bench test was performed using a flat belt machine (a machine with a flat road surface).

  In this test example, a test was performed on three types of tire types A, B, and C. The tire sizes were all 235 / 45R17. A general passenger car was used as a vehicle on which each tire was mounted.

In performing this test example, the present inventor obtained a CF (cornering force) change tendency for three types of tires, tire types A, B, and C. Here, the CF change tendency in this test example is the CF-SA diagram of the bench test in consideration of the wheel load and slip angle (SA) when passing through the S-shaped road (see FIGS. 5 and 6). ) Represents the sum of the amount of CF change for each unit SA (see FIG. 7) and the length divided by the unit SA. The smaller the CF change index, the better the steering stability. In this test example, as shown in FIG. 9, the value for tire type C was taken as index 100, and relative indices were calculated for other tires (see FIGS. 9A, 9B, and 9C). .
A CF-SA diagram in a conventional vehicle handling stability test method in which a load is statically applied to the front side is also shown in FIGS.

  In addition, the inventor conducted a running test on an S-shaped road up the test course 20 for three types of tires A, B, and C, and obtained a steering steering angle (St steering angle). FIG. 8 shows the St steering angle of each tire.

  And this inventor calculated | required the steering steering amount (St steering amount) about each tire. Here, the St steering amount is expressed as a length by summing up the steering steering angle change amount (St steering angle change amount) per unit time while passing through the S-shaped road in the concept as shown in FIG. Is. The St steering amount of each tire showed the same tendency as the evaluation result of the steering stability by the feeling of the driver (see the evaluation in “cornering property” shown in FIG. 10).

Further, the present inventor obtains the steering steering angular velocity (St steering angular velocity, a value obtained by dividing the St steering amount represented by the length by the time taken to pass the S-shaped road), and the tire type C The relative index was calculated for the other tires with the value being 100. The calculation results are also shown in FIG. 9 (see (a), (d), and (e) of FIG. 9).
Between tires of tire types A, B, and C, the St difference in the St steering angular velocity showed the same tendency as the difference in the CF change tendency. Therefore, it was confirmed that the controllability (steering stability) of the tire can be quantified by obtaining the St steering angular velocity of the tire.

  In addition, it was found from this test example that the tire characteristics (limit controllability) can be visualized more accurately by reviewing the bench test conditions (load conditions) from the actual vehicle running data and narrowing down the SA region.

  The embodiment of the present invention has been described above by including the embodiment including the test example. However, the above embodiment is an example, and various modifications can be made without departing from the scope of the invention. Needless to say, the scope of rights of the present invention is not limited to the above embodiment.

1 is a front view of a driver's seat showing that a disk with an angle scale is fixed to a boss portion of a steering wheel of a vehicle and a steering angle meter is attached in an embodiment of the present invention. 1 is a side view of a driver's seat showing that a disk with an angle scale is fixed to a boss portion of a steering wheel of a vehicle and a steering angle meter is attached in an embodiment of the present invention. FIG. 5 is a schematic plan view for explaining a steering angle of a steering wheel in an embodiment of the present invention. It is a partial top view which shows the test course used by one Embodiment of this invention. It is a CF-SA diagram created in a test example. It is the CF-SA diagram which took out a part of FIG. In a test example, it is explanatory drawing explaining calculating | requiring and summing the Y direction component for every unit SA by making SA into a horizontal axis. In a test example, it is a graph which shows the relationship between the passage time in a test course, and a steering angle. In the test example, with reference to the tire type C (a), CF change tendency (b, c), steering steering angular velocity (d, e) when a static load is applied in the conventional vehicle steering stability test method, And it is explanatory drawing which showed the CF change tendency (f, g) at the time of applying a load at the time of driving | running | working with the index | exponent. It is explanatory drawing which shows the evaluation result of the steering stability by a driver's feeling.

Explanation of symbols

14 Steering wheel 20 Test course (course)

Claims (4)

A vehicle maneuvering stability test method for evaluating a vehicle by comparing a maneuvering stability performance of a vehicle by running a vehicle on a predetermined course at a specified speed,
A vehicle steering stability test method in which the steering angle of the steering wheel is measured at regular intervals, and the steering stability is better as the average value of the steering wheel angular velocity is smaller.   The vehicle handling stability test method according to claim 1, wherein the certain course is a course including a continuous corner where the steering wheel needs to be turned back and forth.   The predetermined time is 0.02 second or more and shorter than 0.1 second, the average value of the steering wheel angular velocity is the sum of the change amount of the steering wheel steering angle per the predetermined time. 3. The vehicle handling stability test method according to claim 1, wherein the vehicle handling stability test method is obtained by dividing the course by the time traveled.   The vehicle steering stability test method according to any one of claims 1 to 3, wherein a tire type attached to the vehicle is changed and compared for evaluation.

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