JP3063503B2 - Rotating body balance measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating body balance measuring device for measuring the unbalance of a rotating body such as a tire.

[0002]

2. Description of the Related Art When tires are unbalanced, steering shimmy and vehicle body vibration may occur. For this reason, recently, as shown in JP-A-63-266331, the tire unbalance vector (the amount of unbalance,
An imbalance phase is measured, and a correction weight capable of correcting the imbalance is attached to the tire.

In a conventional tire balance measuring device, various unbalances are added to a tire having no unbalance, and a vibration when the tire is rotated is detected.
The relationship between unbalance and vibration, i.e., the unbalanced vibration characteristics is determined in advance, the vibration when the tire whose unbalance is to be measured is rotated is detected, and the tire unbalance is estimated from the unbalanced vibration characteristics. ing.

[0004]

However, in such a tire balance measuring apparatus, since the vibration level is small, the sensitivity of the vibration detecting means and the influence of other vibrations of the vehicle and the like become large. The imbalance cannot be measured accurately. In particular, when the unbalance amount is small, for example, 5 g, as shown in FIG.
When the true unbalance vector is Vun, the measured unbalance vector varies like Vuna and Vunb. Even when the amount of unbalance is relatively large, the measured unbalance phase may deviate from the true unbalance phase by ± 10 to 20 °.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a rotating body balance measuring device capable of accurately measuring imbalance.

[0006]

In order to achieve the above object, according to the present invention, a rotation detecting means for detecting a rotation state of a rotating body having a predetermined amount of weight added to a predetermined position, and rotating the rotating body. Vibration detecting means for detecting a vibration state in the case where the rotation of the rotating body has been performed; measuring unbalance vector calculating means for obtaining an unbalance vector of the rotating body, that is, a measurement unbalance vector from the rotating state and the vibration state of the rotating body; Unbalance vector storage means for storing a predetermined weight unbalance vector when the predetermined amount of weight is added to the predetermined position on the body; and a true unbalance for obtaining a difference between the measured unbalance vector and the predetermined weight unbalance vector. And a balance vector calculating means.

[0007] Further, rotation detecting means for detecting a rotating state of the rotating body having a predetermined amount of weight added to a predetermined position, vibration detecting means for detecting a vibration state when the rotating body is rotated, and A measurement unbalance vector calculating means for obtaining an unbalance vector of the rotating body, that is, a measurement unbalance vector from the rotating state and the vibration state of the rotating body, and a case where the predetermined amount of weight is added to the predetermined position on the rotating body without unbalance. An unbalance vector detecting means for obtaining a predetermined weight unbalance vector and a true unbalance vector calculating means for obtaining a difference between the measured unbalance vector and the predetermined weight unbalance vector are provided.

[0008]

In this rotating body balance measuring device, a large amount of vibration can be detected by detecting a rotating state and a vibration state by applying a predetermined amount of weight to the rotating body at a predetermined position. In addition, the influence of other vibrations and the like of the vehicle is reduced.

[0009]

1 is a schematic block diagram showing a tire balance measuring device according to the present invention. As shown in the figure, a rotation detecting means 100 is provided for detecting rotation of a tire attached to a vehicle body and having a predetermined amount of weight added to a predetermined position, and a vibration detecting means for detecting vibration when the tire is rotated. 101 is provided, and frequency analysis means 102 for frequency-analyzing the detection signal of the rotation detection means 100 and the detection signal of the vibration detection means 101 is provided.
Power spectrum value detecting means 103 for obtaining the vibration power spectrum value at the primary rotational frequency in the output signal of
And a phase difference detecting means 104 for obtaining a phase difference between rotation and vibration from a result of Fourier transform corresponding to a rotation power spectrum value at a rotation primary frequency and a vibration power spectrum value from an output signal of the frequency analysis means 102. And
From the output signals of the vibration power spectrum value detecting means 103 and the phase difference detecting means 104, the measured unbalance vector Vp
Is provided, and the frequency analysis means 102, the vibration power spectrum value detection means 103, the phase difference detection means 104, and the unbalance vector calculation means 105 calculate the measurement unbalance vector Vp. Means 10
9 are configured. Further, there is provided an unbalance vector storage means 106 for storing a predetermined weight unbalance vector Vo when a predetermined amount of weight is added to a predetermined position to an unbalanced tire. here,
The magnitude of the predetermined weight imbalance vector Vo corresponds to the weight of the weight. Then, there is provided a true unbalance vector calculating means 107 for obtaining a difference between the measured unbalance vector Vp and the predetermined weight unbalance vector Vo, that is, a true unbalance vector Vun estimated as an unbalance vector of the tire itself to be measured. A true unbalance amount / phase calculating means 108 for calculating a true unbalance amount and a true unbalance phase from the unbalance vector Vun is provided. Here, since the magnitude of the predetermined weight imbalance vector Vo corresponds to the weight of the weight, the magnitude of the predetermined weight imbalance vector Vo is estimated as the true unbalance vector Vu.
The true unbalance amount (weight) is determined from the ratio to the size of n.

Next, the operation of the tire balance measuring device shown in FIG. 1 will be described. First, a tire having no imbalance was mounted on a vehicle, a weight of 20 g was added to a position where the phase of the tire was 0 °, and the tire was moved at a vehicle speed of 11 °.
An unbalance vector when rotating at a rotation speed of 0 km, that is, a predetermined weight unbalance vector Vo is obtained, and the predetermined weight unbalance vector Vo is stored in the unbalance vector storage means 106. Next,
A tire whose unbalance is to be measured is mounted on a vehicle, a weight of 20 g is added to a position where the phase of the tire is 0 °, and measurement is started with the tire rotated at a rotation speed at which the vehicle speed becomes 110 km. The means 100 detects the rotation of the tire, and the vibration detecting means 101 detects the vibration of the tire. Next, the frequency analysis means 102
Are the detection signal of the rotation detecting means 100 and the vibration detecting means 101
The vibration power spectrum value detecting means 103 obtains the vibration power spectrum value at the rotation primary frequency from the output signal of the frequency analyzing means 102, and the phase difference detecting means 104 outputs the output signal of the frequency analyzing means 102. The phase difference between rotation and vibration is obtained from
3. The measurement unbalance vector Vp is obtained from the output signal of the phase difference detection means 104. Next, the true unbalance vector calculating means 107 calculates the measured unbalance vector Vp.
A true unbalance vector Vun as shown in FIG. 2 is obtained from a difference between the true unbalance vector Vo and the predetermined weight unbalance vector Vo. The phase θun is calculated.

In such a tire balance measuring device, by adding a predetermined amount of weight to the tire at a predetermined position, the rotation state and vibration state of the tire are detected while the unbalance amount is increased. Since a large vibration level can be detected, the sensitivity of the vibration detecting means 101 and the influence of other vibrations of the vehicle and the like are reduced. For this reason,
Since the S / N ratio is improved, the imbalance can be accurately measured.

FIG. 3 is a diagram showing another tire balance measuring device according to the present invention, and FIG. 4 is a block diagram of the tire balance measuring device shown in FIG. As shown in the figure, a spindle 6 is connected and supported to the strut 4 and the suspension lower arm 5, and the hub 3 is attached to the spindle 6,
The left and right front wheels 1 of the tire 1 are connected to the hub 3 by bolts and nuts, a weight 14 having a weight Wo is added to the tire 1, and an acceleration sensor 7 serving as vibration detecting means is attached to the spindle 6 by bonding or the like. The reflection tape 8 is placed at the same phase position as the weights 14 of the left and right tires 1.
Is attached, an optical fiber sensor 10 serving as rotation detecting means is arranged facing the reflection tape 8, an amplifier 11 is connected to the acceleration sensor 7, an optical fiber sensor amplifier 12 is connected to the optical fiber sensor 10, and an amplifier 11, the optical fiber sensor amplifier 12 is connected to the anti-aliasing filter 203,
3 is the A / D converter 2 of the microcomputer 201
02, a vehicle type information input device 21, a start switch 22, and a cancel switch 23 for inputting a vehicle type and specification information from a card inserted into the card reader are provided, and the vehicle type information input device 21, the start switch 22, and the cancel switch 23 are provided. Is connected to the interface circuit 204, the interface circuit 204 is connected to the microcomputer 201, and the microcomputer 201 supplies the measurement end lamp 24, the liquid crystal display 205,
6, the microcomputer 201 has an unbalance vector measuring means, an unbalance vector storing means, a true unbalance vector calculating means, and a true unbalance amount / phase calculating means. 5 are stored in the microcomputer 201, the interface circuit 204, and the liquid crystal display 20.
5. The analysis device main body 13 is constituted by the printer 206 and the like.

Next, the operation of the tire balance measuring device shown in FIGS. 3 and 4 will be described. First, when a worker turns on a power supply (not shown), initialization of input / output ports, memory clear, and the like are performed (step S1). Next, the vehicle type and specifications are determined by the vehicle type information input device 21 (step S2). Next, the worker adds a weight 14 having a weight Wo to the tire 1 and
The reflective tape 8 is attached to the same phase position as above, the vehicle on which the tire 1 is mounted is put into a free roller, and the vehicle speed, that is, the rotation speed of the left and right tires 1 is set to a predetermined value.
When the start switch 22 is turned on, the acceleration sensor 7 and the optical fiber sensor 10 detect the vibration and rotation of the left and right tires 1, and the A / D converter 202 controls the acceleration sensor 7 and the optical fiber sensor 10 at a sampling speed of 8 msec. A / D conversion is performed on the signal, and A / D conversion is repeated until the sampling number Ns becomes 256, and the vibration digital data and the rotation digital data are stored at predetermined addresses in the memory of the microcomputer 201 (steps S3 to S5). Next, the microcomputer 201 performs fast Fourier transform (FFT) of the vibration digital data and the rotation digital data.
Processing, and calculating the absolute value in each processing result to obtain a vibration power spectrum and a rotation power spectrum,
The primary rotational frequency f1 is obtained from the rotational power spectrum,
The vibration power spectrum value Gp at the rotation primary frequency f1 is obtained, and the rotation signal is subjected to the fast Fourier transform processing.
The Fourier transform result at the primary frequency f1 and the vibration signal
In the fast Fourier transform processing, the rotation primary frequency f1
The phase difference θp between the two is obtained from the Fourier transform result, and the measurement unbalance vector Vp is obtained from the vibration power spectrum value Gp and the phase difference θp (steps S6 to S10). Next, a predetermined weight unbalance vector Vo corresponding to the vehicle type and specification as shown in FIGS. 6 and 7 is read from the memory, and a true unbalance vector Vun is obtained from the difference between the measured unbalance vector Vp and the predetermined weight unbalance vector Vo. Is calculated, and the true unbalance amount Un and the true unbalance phase θun are calculated from the true unbalance vector Vun (steps S11 to S14). Here, assuming that the magnitudes of the estimated true unbalance vector Vun and the predetermined weight unbalance vector Vo are | Vun | and | Vo |, the magnitude | Vo | corresponds to the weight Wo of the weight 14 as described above. , The true unbalance amount Un estimated from the ratio between the magnitude | Vun | and the magnitude | Vo |. That is, the true unbalance amount Un is obtained by the following equation.

Un = Wo × | Vun | / | Vo | Further, the unbalance phase of the true unbalance vector Vun is θ ₁ , the unbalance phase of the predetermined weight unbalance vector Vo is θo, and the true unbalance vector Vun is the x direction. If the component and y-direction component are Ux and Uy, the predetermined weight
Direction of unbalance vector Vo and true unbalance vector
The angle formed by the direction of the torque Vun, that is, the true unbalance phase θun is obtained by the following equation. That is, tire vibration
When detecting an elastic body such as a bush or tire of a vehicle
Due to the influence of
Changes (phase delay), but this phase delay
For tires without a lance, a predetermined amount of weight
It is determined from the vibration characteristics when a light is added. That
When calculating the true unbalance phase θun,
That is, the unbalance of the predetermined weight imbalance vector Vo
It is necessary to correct only the balance phase θo.

Θun = θ ₁ −θo = tan ~ ¹ (Ux / Uy) −θo And, for example, as a result of the measurement, the true unbalance of the tire 1 is obtained.
The quantity Un is 5 g and the true unbalance phase θun is 10 degrees
Sometimes the direction of the weight 14 of the tire 1 is
5g unbalance in direction separated by 10 degrees
Will do. Next, the corrected weight amount is determined in steps of 2.5 g or 5 g from the true unbalance amount Un, the corrected phase is calculated from the true unbalance phase θun , the corrected weight amount and the corrected phase are displayed on the liquid crystal display 205, and the true unbalance amount is displayed. After the balance amount Un, the true unbalance phase θun, the correction weight amount, and the correction phase are printed by the printer 206, the measurement end lamp 24 is turned on (steps S15 to S16).

In such a tire balance measuring device, since the rotation of the tire in which a predetermined amount of weight is added to a predetermined position is detected, the unbalance amount of the tire is 5 g.
, The measurement accuracy of the imbalance was remarkably improved. Further, when the unbalance amount is about 20 g, the variation of the unbalance phase measured by the conventional apparatus is ± 2.
When the amount of unbalance was about 20 g, the dispersion of the unbalance phase measured by the apparatus shown in FIGS. 3 and 4 was ± 9.4 °, and the measurement accuracy of the unbalance phase was 1 °. Significantly improved. As a result, for example, when the imbalance having the unbalance amount of 20 g is corrected, the conventional device has the maximum absolute value of the corrected imbalance amount of 7.2 g. In the device shown in (1), the maximum value of the absolute value of the unbalance amount after the correction is 3.3.
g. For this reason, the steering shimmy and the vehicle body vibration were reduced to -6 dB or less, which is half of the conventional one.

In the above embodiment, the tire balance measuring device has been described. However, the present invention can also be applied to a rotating body balance measuring device for measuring the unbalance of another rotating body such as a propeller shaft. Also,
In the above embodiment, the unbalance vector storage means 10 stores a predetermined weight unbalance vector when a predetermined weight is added to a tire having no unbalance.
Although 6 is provided, an unbalance vector detecting means for obtaining a predetermined weight imbalance vector when a predetermined weight is added to a rotating body having no imbalance may be provided. Further, in the above-described embodiment, the unbalance of the left and right front wheels is measured simultaneously, but only the unbalance of one wheel may be measured, or the unbalance of four wheels may be measured simultaneously. Further, in the above-described embodiment, a weight of 20 g is added to the position where the phase of the tire is 0 °, and the tire is rotated at a rotational speed at which the vehicle speed becomes 110 km. However, it is natural that the present invention is not limited to these values. In addition, Japanese Patent Application 5
As described in the specification of Japanese Patent No. 2595, a peak of a change in the vibration power spectrum is detected, an average value of the peak is calculated, and the number of the peaks in a predetermined range around the average of the peak is calculated. And when the count value is equal to or greater than a predetermined value, the vibration power spectrum value Gp at the primary rotation frequency f1 is obtained.
, And a rotation signal Fourier at the rotation primary frequency f1.
The phase difference θp between them is obtained from the D- transform result and the vibration signal Fourier transform result, and the vibration power spectrum value Gp and the phase difference θ
The measurement unbalance vector Vp may be obtained from p.

[0018]

As described above, in the rotating body balance measuring apparatus according to the present invention, the sensitivity of the vibration detecting means and the influence of other vibrations of the vehicle are reduced, so that the S / N ratio is reduced.
Since the ratio is improved, the imbalance can be accurately measured.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing a tire balance measuring device according to the present invention.

FIG. 2 is a diagram for explaining the operation of the tire balance measuring device shown in FIG.

FIG. 3 is a diagram showing another tire balance measuring device according to the present invention.

FIG. 4 is a block diagram of the tire balance measuring device shown in FIG.

FIG. 5 is a flowchart of an operation of the tire balance measuring device shown in FIGS. 3 and 4;

FIG. 6 is a diagram for explaining the operation of the tire balance measuring device shown in FIGS. 3 and 4.

FIG. 7 is a diagram for explaining the operation of the tire balance measuring device shown in FIGS. 3 and 4;

FIG. 8 is a diagram for explaining the operation of a conventional tire balance measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tire 7 ... Acceleration sensor 10 ... Optical fiber sensor 13 ... Analysis device main body 100 ... Rotation detection means 101 ... Vibration detection means 106 ... Unbalance vector storage means 107 ... True unbalance vector calculation means 109 ... Measurement unbalance vector calculation means

Claims (2)

(57) [Claims] 1. A rotation detecting means for detecting a rotation state of a rotating body having a predetermined amount of weight added to a predetermined position, a vibration detecting means for detecting a vibration state when the rotating body is rotated, and the rotating body. Measurement unbalance vector calculating means for obtaining an unbalance vector of the rotating body, that is, a measurement unbalance vector from the rotation state and the vibration state of
Unbalance vector storage means for storing a predetermined weight unbalance vector when the predetermined amount of weight is added to the predetermined position on a rotating body without unbalance;
A rotating body balance measuring device, comprising: a true unbalance vector calculating means for calculating a difference between the measured unbalance vector and the predetermined weight unbalance vector. 2. A rotation detecting means for detecting a rotation state of a rotating body having a predetermined amount of weight added to a predetermined position; a vibration detecting means for detecting a vibration state when the rotating body is rotated; Measurement unbalance vector calculating means for obtaining an unbalance vector of the rotating body, that is, a measurement unbalance vector from the rotation state and the vibration state of
An unbalance vector detecting means for obtaining a predetermined weight unbalance vector when the predetermined amount of weight is added to the predetermined position to the unbalanced rotating body; and a difference between the measured unbalance vector and the predetermined weight unbalance vector. And a true unbalance vector calculating means for obtaining the following.