JPH0561489B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for reducing vehicle vibration, particularly vibrations caused by unevenness and unbalance of a vehicle in which tires and wheels are assembled. The present invention relates to a method for reducing vehicle vibration, in which wheel vibration input to a vehicle, etc., is reduced at a rotational speed equal to the resonance frequency of the vehicle body, steering, etc.

[Conventional technology]

When the vehicle is running, vehicle resonances that occur due to input from the vehicle, that is, the assembly of tires and wheels, generally include vehicle resonance and steering resonance, and the vibration frequency input from the wheels and the resonance frequency of the vehicle side When they match, it is amplified and becomes felt as an unpleasant resonance. The causes of vibrations in the front wheels include non-uniform mass distribution along the wheel circumferential direction, non-uniform stiffness distribution, and non-uniform wheel radius distribution.

Uneven or biased mass distribution is called unbalance, and as shown in Figure 1, when there is an unbalanced mass m at a distance r from the rotation axis of the wheel 1, the magnitude of the unbalance is Becomes an mr. When this wheel 1 rotates at an angular velocity ω, a centrifugal force of mrω ² is generated, and its sine component mrω ² ·sin θ (see FIG. 2) becomes a vertical vibration input to the vehicle body. The position and magnitude of unbalance are measured by a balancing machine from vibrations or centrifugal force caused by unbalance during rotation.

On the other hand, non-uniform stiffness distribution is caused by non-uniform tires made of multiple components, and non-uniform wheel radius distribution is caused by unevenness of the wheel, eccentricity of the pitch circle of the wheel mounting bolt hole, etc. Non-uniformity in rigidity distribution and wheel radius distribution is determined by using a uniformity machine to measure the radial load variation (RFV) that the rotating drum receives when the vehicle and the rotating drum are rotated while keeping the distance between their axes constant. It can be obtained by The radial load applied to the rotating drum varies as shown in FIG.

By the way, in the past, the above imbalance,
The following methods are used to reduce wheel vibration due to non-uniform rigidity and non-uniform radius. First, there is a way to correct imbalance by installing balance weights. To correct the uneven radius, there are two methods: grinding the tire with a special grinder to correct it, or measuring the radius distribution of each tire and wheel, and then assembling the tires by matching the maximum radius position of the tire with the minimum radius position of the wheel. . In addition, as a correction for stiffness and radial non-uniformity, the peak position of the tire radial load variation curve (A in Figure 3)
Various measures have been taken, such as assembling the wheel by aligning the wheel's minimum radius position with the wheel's lowest radius position.

[Problem to be solved by the invention]

However, conventional measures to reduce wheel vibration are
As mentioned above, the correction of unbalance and the correction of stiffness or radial non-uniformity are made separately, so the difference between the load due to unbalance and the radial load fluctuation due to stiffness or radial non-uniformity is In some cases, the phase difference was random, and the unbalanced load and the radial load fluctuation overlapped so as to reinforce each other, resulting in an excessive excitation force toward the vehicle body.

The present invention has been created in view of the above-mentioned conventional problems and to effectively solve them.

The object of the present invention is to reduce vibration input from the wheels to the vehicle body by canceling it out at the resonance vehicle speed of the vehicle body, steering, etc., that is, the angular velocity of the wheels;
It is an object of the present invention to provide a method for reducing vehicle vibration, which can suppress vibrations of the vehicle body, steering, etc., and improve vehicle comfort and safety.

[Means to solve the problem]

In order to achieve the above object, the method for reducing vehicle vibration of the present invention provides the peak position of the Fourier first-order component of the radial load fluctuation curve and the amount of radial load fluctuation based on the non-uniformity of the vehicle in which tires and wheels are assembled. , as well as the position and size of wheel unbalance, and calculate the Fourier first component of the radial load fluctuation due to nonuniformity and the unbalance at the wheel rotation speed corresponding to the vehicle running speed at which vehicle resonance occurs. The position and mass of the balance are adjusted so that the centrifugal force and the centrifugal force caused by the balance are adjusted to cancel each other out.

[Embodiments of the invention]

The method of the present invention will be explained in detail below with reference to the accompanying drawings. First, as shown in FIG. 1, a wheel 1, which is an assembly of a tire 2 and a wheel 3, is filled with air, and then the radial load fluctuation of the wheel 1 is measured using a uniformity machine. This load variation can be obtained by measuring the radial load applied to the rotary drum when the wheel 1 and the rotary drum are rotated while being pressed against each other while keeping the distance between their axes constant. In addition, the radial load fluctuation can be calculated from the change in the effective radius of the wheel 1 (the shortest distance from the axis of the wheel to the contact point between the rotating drum and the wheel) when the wheel 1 is rotated while being pressed against the rotating drum with a constant load. It may be calculated.

FIG. 3 shows an example of a radial load variation curve.
As described above, this curve 4 fluctuates based on non-uniform rigidity and non-uniform radius of the wheel 1, and changes every rotation of the wheel 1. The difference between the maximum value and the minimum value of curve 4 is the value D of the radial load variation RFV, and this value D is a measure of stiffness and radius non-uniformity. FIG. 4 shows the Fourier first-order component 5 of the curve 4 in FIG.
From this, the peak position B and bottom position C of the radial load fluctuation are determined. In curve 4 in FIG. 3, the peak position and bottom position are not necessarily symmetrical, so it is appropriate to determine these positions from the Fourier first-order component of curve 5. In addition, as the value of the radial load fluctuation RFV, the value of RFV of the first-order component 5 is d
Use. When the peak position B is on the road surface 6 side as shown in FIG.
The excitation force f ₁ is the maximum, and conversely, the excitation force f ₁ is the minimum when the bottom position C is on the road surface 6 side.

Next, the position and magnitude of the unbalance of the wheel 1 are measured using a balancing machine. The balancing machine measures the vibration or centrifugal force caused by unbalance when the wheel 1 is rotated, and thereby determines the position and magnitude mr of the unbalance as shown in FIG. When wheel 1 with an unbalance of magnitude mr rotates at an angular velocity ω,
mrω ² ·sinθ becomes the excitation force that vibrates the vehicle body etc. up and down, and this excitation force fluctuates as shown in Fig. 2. The value of RFV conversion due to this excitation force or unbalanced load is the difference between the peak position H and the bottom position G, so it is 2mrω ² . Moreover, as shown in FIG. 6, the unbalance mass m, that is, the peak position H is at the road surface
When the wheels 1 are on the side, the excitation force f ₂ that pulls down the vehicle body, steering, etc. toward the road surface 6 is maximum, and conversely, when the bottom position G is on the road surface 6 side, the excitation force f 2 from the wheels 1 that lifts the vehicle body, etc. is the maximum.

FIG. 7 shows the relationship between the two vibration inputs or excitation forces applied from the wheels to the vehicle body and the vehicle speed. In the figure, a and b are excitation forces due to radial load fluctuations RFV based on wheel rigidity and radial non-uniformity, and a is excitation force due to unbalanced loads. RFV, which is based on non-uniformity of rigidity and radius, is determined by the static state of the wheel, so it does not depend on the wheel's angular velocity ω, speed, or vehicle speed, and the excitation forces A and B are constant as shown. On the other hand, since the excitation force a due to the unbalanced load is based on centrifugal force, it increases in proportion to the square of the vehicle speed.

Excitation force a is in the same phase as excitation force a due to unbalance. In this case, excitation force a and a overlap and strengthen each other, and a large excitation force b is applied to the vehicle body side. . To further explain this case using FIG. 8, the peak position B of RFV based on non-uniformity,
The peak position H of the RFV based on the unbalance (the position of the unbalanced mass) corresponds to when the wheel 1 is placed on the opposite side by J degrees with respect to the center of the wheel 1 as shown in the figure. With this arrangement, it is based on non-uniformity.
Excitation force f ₁ due to RFV and excitation force f ₂ due to unbalance
A large excitation force is applied to the vehicle body side in the same direction and strengthens each other.

On the other hand, the excitation force b is the excitation force a due to unbalance.
In this case, the excitation forces a and b cancel each other out and weaken each other, and the total excitation force applied to the vehicle body side becomes c. To further explain this case with reference to FIG. 9, the peak position B of RFV due to non-uniformity and the peak position H of RFV due to unbalanced load are
When they are arranged in the same phase above, the excitation force f ₁ due to non-uniform contact and the excitation force f ₂ due to unbalance are in opposite directions and cancel each other out, resulting in a small input to the vehicle body.

Conventionally, the phase difference between the radial load fluctuation due to non-uniformity and the load due to unbalance is not considered at all, and the peak position B of RFV due to non-uniformity is
The peak position H of the unbalanced load RFV is completely random for each wheel.
Therefore, the total excitation force applied to the vehicle body side from the wheels varied between b to c in FIG. 7. As described above, the vehicle body, steering wheel, etc. each have a fixed natural frequency or resonant frequency, and vibrate violently when a vibration input at the resonant frequency is applied. Therefore, at the vehicle speed (resonant vehicle speed) X when the wheel rotation speed is equal to this resonance frequency, the maximum I
There was a wheel with vibration input of .

The present invention reverses the phases of two elements of vibration input from the wheels to the vehicle body, namely RFV due to nonuniformity and RFV due to centrifugal force due to unbalance, and generates resonance in the vehicle especially when the wheels are mounted. At the wheel rotation speed corresponding to the vehicle speed, the RFV due to the unbalanced load of the same magnitude as the RFV due to non-uniformity is applied in the opposite direction to cancel it out, and the vibration input to the vehicle body is It will look like c in the figure. This will be explained with reference to FIG.

As shown in Fig. 10, the unbalanced position (the peak position of RFV of the unbalanced load) H of the wheel 1 with the tire and wheel assembled, and the
It generally does not coincide with the peak position B of RFV. In order to correct the unbalance, it is sufficient to attach a balance mass _M1 of equal size to the opposite side of the unbalance position H with respect to the center of the wheel 1. for example,
As shown in FIG. 11, an unbalanced mass m ₁ is located at a distance r ₁ in the radial direction and a distance 1 ₁ in the width direction from the center O of the wheel 1.
When there is a static unbalance amount (centrifugal force) F ₁ = m ₁ r ₁ ω ² due to this unbalanced mass m ₁
and the dynamic unbalance amount (unbalance moment) P ₁ = F ₁ l ₁ , and the center O and the unbalance mass
Balance masses m ₂ and m ₃ may be placed symmetrically as shown in the figure at a distance r ₁ in the radial direction and a distance 1 in the width direction from the center O in a plane including m ₁ . The sizes of m ₂ and m ₃ are calculated from the balance between the static unbalance amount and the dynamic unbalance amount. That is, m ₁ r ₁ =
It is determined from two equations: r(m ₂ +m ₃ ) and m ₁ r ₁ l ₁ =(m ₂ −m ₃ )rl. Note that the balance masses m ₂ and m ₃ are the first
As shown in Fig. 2, it consists of a leaf spring 7 and a lead weight 8, and is attached to the ear of a rim wheel 9, etc., as shown in Fig. 13. However, in FIG. 10, even if the balance mass M ₁ is installed on the opposite side from the unbalance position H, the
RFV will remain. Therefore, in the present invention, in order to cancel out the RFV caused by non-uniformity, an unbalanced load of the same magnitude as the RFV caused by non-uniformity is applied in the opposite direction at a resonant vehicle speed corresponding to the resonance frequency of the vehicle body or steering. A balance mass _M2 is provided at the peak position B.

As mentioned above, if the balance masses M ₁ and M ₂ are installed in two locations, two balance masses are required each on the front and back sides of the wheel 1 as shown in Figure 11, so a total of four balance masses can be installed. Become. However, if a balance mass M 0 which is a combination of these balance masses M ₀ is provided at a predetermined position between balance masses M ₁ and M ₂ , it is necessary to install two balance masses in one place. For example, the position and size of the balance mass M ₀ are determined from the composite vector V 0 of the vector V ₁ of the centrifugal force of the balance mass M ₁ and the vector V ₂ of the centrifugal force of the balance mass M ₂ , as shown in the _figure . That is, the peripheral edge of wheel 1 on the extension line of this resultant vector V ₀
A balance mass of size M ₀ is provided at the position of V ₀ .

As described above, in the present invention, the unbalanced load at the resonant vehicle speed and the radial load fluctuation due to non-uniformity are offset by the balance mass, so the vibration input from the wheels to the vehicle body becomes weak. It is possible to suppress the occurrence of resonance in the vehicle body, steering, etc. Therefore, the ride comfort of the vehicle is improved, the handling performance is improved, and safety can be further improved. Note that when the vehicle speed deviates from the resonant vehicle speed that corresponds to the resonance frequency of the vehicle body, steering, etc., the vibration input to the vehicle body gradually increases from c in Figure 7, but since it deviates from the resonant vehicle speed, the Vibration is hardly a problem.

In addition, in the present invention, the radial load fluctuation and unbalance are measured on the whole wheel including the tire body and the wheel, so the number of measurements can be reduced, and the radial load fluctuation and unbalance are measured with the same measuring device. If you do this, you can measure by just installing and removing the wheel once. Furthermore, RFV
It is also possible to mark the peak position and unbalance position on the wheels, but a device equipped with a computer that memorizes these values and can calculate the position and size of the balance mass makes it easier to install the balance mass. can be done.

〔Effect of the invention〕

As described above, the method for reducing vehicle vibration of the present invention is based on the peak position of the Fourier first-order component of the radial load fluctuation curve, the amount of radial load fluctuation, and the wheel Find the position and magnitude of the unbalance, and calculate the Fourier first-order component of the radial load fluctuation due to nonuniformity and the centrifugal force due to the unbalance at the wheel rotation speed corresponding to the vehicle running speed at which vehicle resonance occurs. The balance position and mass are adjusted so as to cancel each other out.
Vibration input from the wheels to the vehicle body side can be significantly reduced, especially at vehicle speeds where the vehicle body, steering, etc. resonate, suppressing resonance in the vehicle body, steering, etc., improving vehicle comfort and maneuverability, and easily and inexpensively. It is possible to achieve excellent effects such as practical implementation.

[Brief explanation of drawings]

Fig. 1 is a front view for explaining wheel unbalance, Fig. 2 is a graph showing vertical vibration input due to unbalance, Fig. 3 is a graph showing the radial load fluctuation curve of the wheel, and Fig. 4 is a graph showing the vibration input in the vertical direction due to unbalance. The figure is a graph showing the Fourier first-order component of the same radial load variation curve, Figure 5 is a front view illustrating the excitation force due to uneven wheels, and Figure 6 is a front view illustrating the excitation force due to unbalanced wheels. The front view, Figure 7 is a graph showing the relationship between the excitation force due to wheel vibration and vehicle speed, and Figures 8 and 9 are graphs showing the case where the vibration input due to uneven vibration input due to wheel imbalance is in the same phase. FIG. 10 is a front view showing an embodiment in which the method of the present invention is applied to a wheel, FIG. 11 is a side sectional view showing balance correction, and FIG. 12 is a diagram showing the balance weight. A side view showing an example, and FIG. 13 is a side sectional view showing a state in which the balance weight is attached to a wheel. In the figure, 1 is a wheel, 2 is a tire, 3 is a wheel,
4 is the radial load variation curve, 5 is the Fourier first-order component of the radial load variation curve, 6 is the road surface, 7 is the leaf spring, 8 is the weight, B is the peak position of the Fourier first-order component, and a is the addition due to unbalance. Vibration forces A and B are excitation forces due to non-uniformity, b is the combined excitation force of a and b, c is the combined excitation force of a and b, and X is the resonant vehicle speed.

Claims (1)

[Claims] 1. Determine the peak position and amount of radial load fluctuation of the Fourier first-order component of the radial load fluctuation curve based on the unevenness of the wheels assembled with tires and wheels, as well as the position and size of the unbalanced wheels, and calculate the resonance of the vehicle. The balance position and mass are adjusted so that the Fourier first-order component of the radial load fluctuation due to non-uniformity and the centrifugal force due to unbalance cancel each other out at the wheel rotation speed corresponding to the vehicle running speed at which A method for reducing vehicle vibration characterized by adjusting the vibration.