JPS6234541B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for correcting non-uniformity in a pneumatic tire, and more specifically, the present invention provides a method for correcting non-uniformity in a pneumatic tire.
Variation, hereinafter simply referred to as LFV. ).

It is generally known that non-uniformity occurs in pneumatic tires due to variations in the materials, dimensions, weights, etc. of the constituent members used for manufacturing them, as well as due to molding precision. When we analyze the components of the non-uniformity of this pneumatic tire, we find that the aforementioned LFV component, which affects the straight-line running performance of the car,
Radial Force Variation (Radial Force Variation) is also a cause of vibration and noise in automobiles.
Hereinafter simply referred to as RFV. It can be divided into components such as lateral force deviation (hereinafter simply referred to as LFD) component or conicity component, which impairs the directional stability of a vehicle, which is related to component and maneuverability. .

Therefore, since it is actually impossible for those skilled in the art to manufacture completely uniform pneumatic tires, each of the above-mentioned non-uniformity components is measured using a measuring machine usually called a uniformity machine. Based on the measurement results, each component is polished and corrected as necessary. Regarding this method of polishing correction, for example, correction of LFV component is described in US Patent No. 3946527.
RFV
The modification of the components is described in U.S. Patent No. 3841033, etc.
In addition, since the modification of the LFD component is described in detail in US Pat. According to the measurement results for each component, a small amount of rubber is removed from the tread portion of the pneumatic tire by polishing to make corrections.

However, among the above-mentioned non-uniformity components, it has been found that individual polishing corrections for the RFV component and LFV component are very time-consuming as described above. Specifically, for example,
If the LFV component is polished after the RFV component has been polished, the RFV that was modified first
If the component changes, the RFV component must be measured again to confirm whether it is acceptable or not, and in some cases, another polishing correction may be required. Furthermore, depending on the state of change, re-polishing may not be possible due to the performance of the pneumatic tire.

In addition, the polishing corrections for the LFV component mentioned above are all corrections made when the pneumatic tire rotates in one direction, and not when the pneumatic tire rotates in the opposite direction, so the use of this corrected pneumatic tire In this case, it is necessary to match the running direction, for example, it is necessary to mark the direction of rotation on the sidewall of a pneumatic tire, and it is also necessary to select the direction of rotation when installing it on the left and right sides of a car.
This is also very time consuming.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the above-mentioned conventional drawbacks and improve the RFV
To provide a method for correcting nonuniformity of a pneumatic tire, which can reduce the LFV component without changing the component, and can simultaneously reduce each LFV component in the forward and reverse rotations of the pneumatic tire. It is.

In order to achieve the above object, the present inventors conducted intensive research and found that the LFV component of the non-uniformity component can be reduced by averaging the stiffness of both shoulder sections in the tread section of a pneumatic tire. This was already known, but it was found that the difference in stiffness between the shoulder sections on both sides correlated with the difference in radius between the shoulder sections on both sides, and that the RFV component correlated with the composite average value waveform of the radius at the shoulder sections on both sides. Therefore, by measuring the radius of each shoulder part on both sides and averaging the stiffness of the shoulder parts on both sides without changing the calculated average value waveform of the radius, it is possible to reduce the LFV component without changing the RFV component. I thought it could be done. As a result of further research, it was confirmed that the method of the present invention described below can sufficiently achieve the above object.

To summarize the method of the present invention, a pneumatic tire is rotated, the variation in radius of both shoulder parts during one rotation is measured, and then, from the variation in each measured radius, the radius on the circumference of the tire is determined. By determining the variation in the difference, and then averaging the variation in the radius difference, the two-division area on the tire circumference to be polished at both shoulder portions is determined,
Thereafter, within one of the determined areas, the shoulder portion on one side having the smaller radius in comparison of the variations in each radius is polished to a predetermined depth according to the variation in the radius difference, and then Within the area, the one-sided shoulder part on the opposite side to the one-sided shoulder part polished in the above is similarly polished to a predetermined depth according to the variation of the radius difference, and the lateral force generated in the pneumatic tire is This is a method for correcting non-uniformity of a pneumatic tire, characterized in that the variation in the amount of air is reduced.

Next, the method of the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a drawing schematically showing an apparatus for carrying out the method of the present invention, in which a pneumatic tire T is rotatable by a rotary drive shaft 1. In FIG. A road roll 2 is pressed below the pneumatic tire T, and the above-described non-uniformity component occurring in the pneumatic tire T is applied to the road roll 2 as a reaction force.

Of the non-uniformity components, the RFV component is measured by the load cell 3, converted into an electrical signal, and input to the measurement controller 4. The electric signal of the RFV component inputted to the measurement controller 4 is compared with a predetermined tolerance level, and if there is a portion exceeding the tolerance level, the shoulder portions on both sides of the tread portion of the pneumatic tire T corresponding to the portion exceeding the tolerance level are compared. A polishing signal is output to servo amplifiers 5 and 6 for polishing. The abrasive signals amplified by the servo amplifiers 5 and 6 are output to the next grinder operating mechanisms 7 and 8, and the grinding wheels 11 and 12 provided in the grinder mechanisms 9 and 10 are moved to the shoulder portions on both sides of the pneumatic tire T. contact with. In this way, the RFV component is reduced by polishing, and the result can be measured again by the load cell 3 and confirmed by the measurement controller 4.

Further, the load roll 2 is provided with a load cell 13, which can measure the LFV component among the non-uniformity components, and the converted electric signal is input to the measurement recorder 14. This measurement recorder 14 can also record measurement results on chart paper or the like, and can also determine whether or not the measured LFV component exists within a predetermined tolerance level.

On the other hand, from the pressing position of the load roll 2 mentioned above,
Measuring terminals 15 and 16 are provided in contact with both shoulder portions of the pneumatic tire T separated by 90 degrees so that the radii of both shoulder portions can be measured respectively. Each radius of the shoulder portions on both sides measured by the measurement terminals 15 and 16 is converted into an electrical signal and input to the signal processing circuit 17. The signal-processed electrical signals corresponding to each radius from the signal processing circuit 17 are input to the next calculation controller 18, which calculates the difference in radius between the shoulder portions on both sides at each portion on the tire circumference, and also calculates the variation in the radius. is required. Furthermore, as will be described later, this calculation controller 18 determines the polishing positions of both shoulder portions in order to reduce the LFV component, which is a non-uniformity component, and sends polishing signals to the servo amplifiers 5 and 6 in accordance with the determination. Output is also performed.

Figure 2A shows the measurement terminals 1 at both shoulder parts when the pneumatic tire T is rotated once.
5 and 16, the waveform a shows the variation in the radius of the right shoulder part of the pneumatic tire T in Figure 1, and the waveform b shows the radius of the left shoulder part. This is the fluctuation of Further, the waveform c is a composite average value waveform of the fluctuations a and b of each radius of the shoulder portions on both sides, and this waveform c is correlated with the RFV component which is the non-uniformity component as described above.

The respective radii of the shoulder portions on both sides measured by the measurement terminals 15 and 16 are input to the calculation controller 18, where the difference in the radius of the shoulder portions on both sides in each component on the tire circumference is calculated as described above. As shown in Figure 2A, the waveform of the variation d in the radius difference is obtained. The variation d of the radius difference obtained in this way is further averaged (average line e) within the calculation controller 18, and as a result, the waveform of the variation d of the radius difference is divided between the two on the circumference of the tire. It will be divided into areas α and β.

Next, when the two areas α and β are determined as described above, the fluctuations a and b of each radius are compared in the area α, and the one-sided shoulder with the smaller radius fluctuation (higher rigidity) is section is selected. Therefore,
Referring to FIG. 2A, since the radius variation b is smaller than the radius variation a, the left shoulder portion is selected.

When the left side shoulder portion is selected in this way, the calculation controller 18 outputs a grinding signal to the servo amplifier 5, and when the area α reaches the position of the grinding wheel 11, the grinder operating mechanism 7 is actuated. Then, as shown in FIG. 2C, the area f of the shoulder portion on the left side is polished. On the other hand, when the area β reaches the position of the grinding wheel 12, the grinder operating mechanism 8 is operated, and the calculation controller 18 is operated in the same manner to grind the area g of the right shoulder portion as shown in FIG.
A polishing signal is output from the servo amplifier 6 to the servo amplifier 6.

Particular attention should be paid here to the fact that the left side shoulder part must be selected in area α as shown in FIG. 2C, and the right side shoulder part must be polished in area β. Further, each polishing state is to be performed at a predetermined depth from each surface of both shoulder portions according to a variation in the radius difference, that is, approximately 1.0 mm or less, preferably 0.6 mm or less. This is important from the viewpoint of equalizing the stiffness at both shoulder portions.

After performing the polishing correction as described above, the pneumatic tire T is rotated again, the LFV component is measured by the load cell 13, and the LFV component is measured by the measurement recorder 14.
When we confirmed the decrease in the LFV component, we found that Fig. 3A,
As shown in (a), the LFV components in the forward and reverse directions of the pneumatic tire T decreased simultaneously, and it can be confirmed that the LFV components were corrected to within a predetermined permissible level.

Furthermore, as mentioned above, since the RFV component is correlated with the composite average value waveform c of the radius fluctuations a and b shown in Figure 2A, even when the polishing correction is performed as described above, the composite Average value waveform c
Since the area α shown in Figure 2 A uniformly descends according to the polishing depth, and the area β also descends in the same way, in effect, the composite average value waveform c is simply parallel to the downward direction. Just by moving it, the waveform does not change, and therefore the RFV component does not change either.

As described above, according to the present invention, the conventional drawbacks can be solved and the LFV component can be reduced without changing the RFV component due to the non-uniformity of the pneumatic tire. The LFV component can be reduced at the same time, and furthermore, the non-uniformity of pneumatic tires can be corrected quickly, so the effects are very large.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of an apparatus for implementing the method of the present invention, Fig. 2 A to C are explanatory diagrams of the procedure for polishing correction to reduce the LFV component, and Fig. 3 A and I are diagrams showing the method of the present invention. FIG. 2 is a diagram showing the results of measurements of LFV components of pneumatic tires. a and b are variations in the radius of both shoulder portions, d is a variation in the difference in radius, T is a pneumatic tire, and α and β are areas divided into two on the circumference of the tire.

Claims (1)

[Claims] 1 Rotate the pneumatic tire, measure the variation in radius of both shoulder parts during one rotation, and then, from the variation in each measured radius,
By finding the variation in radius difference around the tire circumference and then averaging the variation in radius difference,
Determine the two-divided area on the tire circumference to be polished on both shoulder parts, and then, within one of the determined areas, compare the variation of each radius. Polishing is performed to a predetermined depth according to the variation, and further, within the other determined area, the one-sided shoulder part on the opposite side to the one-sided shoulder part polished in the above is similarly polished to a predetermined depth according to the variation in the radius difference. 1. A method for correcting non-uniformity of a pneumatic tire, characterized in that the method comprises: abrading to a depth of .