JPS6234542B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for correcting tire non-uniformity, and more specifically, lateral force variation (LFV) occurring in a tire.
It is called. ).

BACKGROUND ART It has been known that tires generally suffer from non-uniformity due to variations in the materials, dimensions, weights, etc. of the constituent members used in the manufacture of tires, as well as due to the precision of molding. When we analyze the components of this tire non-uniformity, we find the aforementioned LFV component that affects the straight-line running performance of the vehicle, and the radial force variation (Radial Force Variation) that causes vibrations and noise in the vehicle. (hereinafter simply referred to as RFV) component, and the lateral force deviation (hereinafter simply referred to as LFD) component or conicity component that impairs the directional stability of the vehicle related to maneuverability. It can be divided into what is called.

Therefore, since it is actually impossible for those skilled in the art to manufacture completely uniform 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 polishing correction method, for example, correction of LFV component is described in US Pat. No. 3,946,527 and US Pat. Since it is described in detail in the specification of Patent No. 3739533, etc., the detailed explanation will be omitted here.In general, each non-uniformity component is measured, and the measurement results are used for each component. Correspondingly, a small amount of rubber is removed from the tread area of the tire to correct the problem.

However, among the aforementioned non-uniformity components, the polishing correction of the LFV component is performed only when the tire rotates in one direction, and not when the tire rotates in the opposite direction. When using tires that have been modified, it is necessary to match the running direction, for example, by marking the sidewall of the tire to specify the direction of rotation.
It is also necessary to select when installing on the left and right sides of the car. Furthermore, after completing the correction when rotated in one direction, it is conceivable to rotate in the opposite direction and make the same correction, but this also requires two polishing steps and is very time-consuming.

In addition, for example, if the LFV component is polished after the RFV component has been polished, the previously modified RFV component will change and the
The RFV component must be measured to confirm whether it is acceptable, and in some cases, another polishing correction may be required. Furthermore, depending on the state of the change, re-polishing may not be possible due to the performance of the tire.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the above-mentioned conventional drawbacks and to
components can be reduced at the same time, and
It is an object of the present invention to provide a tire non-uniformity correction method capable of reducing the LFV component without changing the RFV component.

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 portion of the tire. It was known that the difference in stiffness between the shoulder sections on both sides can be calculated by combining the LFV components when the tire is rotated in the forward and reverse directions, and the difference in radius between the shoulder sections on both sides. be correlated with each other, and
It has been found that the RFV component correlates with the composite average value waveform of the radius at both shoulder parts, so if the stiffness of both shoulder parts is averaged so as not to change the composite average value waveform of the radius, the RFV component will not change. We considered that it is possible to simultaneously reduce each LFV component in the forward and reverse rotations of the tire. 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 tire is rotated in forward and reverse directions, each variation in lateral force acting on a supporting surface during one revolution is measured, and then each variation in each measured lateral force is measured. and determine the fluctuation of the average lateral force. Then, by averaging the fluctuations of this average lateral force, the two-divided area on the tire circumference to be polished at both shoulder parts is determined, and then, Within one of the determined areas, the one-sided shoulder portion is polished according to the direction of the average lateral force to a predetermined depth according to the variation of the average lateral force, and further within the other determined area. Then, 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 fluctuation of the average lateral force, and the fluctuation of the lateral force generated in the tire is polished. A method for correcting tire non-uniformity, characterized in that:

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 tire T can be rotated in forward and reverse directions by a rotary drive shaft 1. As shown in FIG. A road roll 2 is pressed below the tire T, and the aforementioned non-uniform component occurring in the 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 input 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 tire T corresponding to the portion exceeding the tolerance level are polished. A polishing signal is output to servo amplifiers 5 and 6 in order to
The grinding signals amplified by the servo amplifiers 5 and 6 are output to the next grinder operating mechanisms 7 and 8, and the grinding holes 11 and 12 provided in the grinder mechanisms 9 and 10 are brought into contact with the shoulder portions on both sides of the tire T. let In this way
The RFV component is reduced by polishing,
The result is measured again by the load cell 3 and can be confirmed by the measurement controller 4.

On the other hand, the load roll 2 is provided with a load cell 13 so that the LFV component among the non-uniformity components can be measured. The LFV component measured by the load cell 13 is converted into an electrical signal and input to the signal processing circuit 14, where each LFV component when the tire rotates in the forward and reverse directions is stored and also each part
It is calculated to combine the LFV components and find the average LFV component. Next, from the average LFV component synthesized and averaged in this way, the polishing positions of the shoulder portions on both sides are determined in order to reduce the LFV component, which is a non-uniformity component, as will be described later, and the polishing signal is determined according to the determination. is outputted to servo amplifiers 5 and 6.

Figure 2A shows the tire T being rotated in forward and reverse directions and measured by the load cell 13 at each rotation.
This shows the LFV component, and the LFV when the tire T is rotated in the forward and reverse directions as shown in the figure.
The components do not show the same waveform, and therefore, as mentioned above, when installing a tire on a car, it is necessary to match the rotation direction or to perform two polishing corrections on the LFV component when rotating in the forward and reverse directions. It is. However, in the present invention, the above-mentioned signal processing circuit 14 matches each LFV component at each part of the tire circumference as shown in FIG. 2A, and calculates the average LFV component as shown in FIG. 2B. . Next, this average LFV component is averaged, and the tire circumference is divided into two zones α and β. Next, when the two areas α and β are determined in this way, signal processing is performed in this area α in order to polish the shoulder portion on the left side of the tire T shown in FIG. 1 from the direction of the average LFV component. A polishing signal is output from the circuit 14 to the servo amplifier 5.
Then, as the tire T rotates, when the left side shoulder part of the tread part of the tire T corresponding to the area α reaches the position of the grinding wheel 11, the grinder operating mechanism 7 is operated, and as shown in FIG. As shown, polish the area a on the left side shoulder part.

On the other hand, when the area β reaches the position of the grinding wheel 12, the grinder operating mechanism 8
Similarly, a polishing signal is outputted from the signal processing circuit 14 to the servo amplifier 6 in order to polish the range b of the shoulder portion on the right side as shown in FIG. 2C.

Particular attention should be paid here to the fact that if the left side shoulder part is selected and polished in the area α as shown in FIG. 2C, the right side shoulder part must be polished in the area β. In addition, each polishing state is set to a predetermined depth from each surface of both shoulder parts according to the average LFV, that is, 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 tire T is rotated again, and the load cell 13
When the LFV component is measured and the decrease in the LFV component is confirmed using the recorder attached to the signal processing circuit 14, as shown in Figure 3 A and B, the LFV component when the tire T is rotated in the forward and reverse directions simultaneously changes. It can be confirmed that the amount has been reduced and corrected to within a predetermined acceptable level.

In addition, to check whether there is any change in the RFV component, use the load cell 3 to measure the RFV component again after polishing and correcting the LFV component.
It should be clear that almost nothing has changed. This is based on the fact that, as described above, the RFV component is correlated with the composite average waveform of fluctuations in each radius of the shoulder portions on both sides. To be more specific, for example, in FIG. 1 and FIG.
The fluctuations c and d of each radius measured by the measurement terminals 15 and 16 are arranged so that a composite average value waveform e can be obtained by the next measurement recorder 17.

Therefore, in the above-mentioned correction of the LFV component, in the area α, the left side shoulder part, which has high rigidity, is ground to a certain depth from the surface, so the second
This means that the large part of the rigidity of the radius variation d in Figure 2D has been uniformly lowered, and since the right side shoulder part has been similarly polished in the area β, the radius in Figure 2D This means that a large part of the stiffness of the fluctuation c has been uniformly lowered, so in effect, the composite average value waveform e has simply been translated downward, and the waveform has hardly changed. This means that the RFV component also does not change.

As described above, according to the present invention, the conventional drawbacks are solved, each LFV component in the forward and reverse rotation of the tire can be reduced simultaneously, and the LFV component can be reduced without changing the RFV component. Furthermore, the effects are very large, such as the ability to quickly correct tire non-uniformity.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of an apparatus for carrying out the method of the present invention, Fig. 2 A to E are explanatory diagrams of the procedure for polishing correction to reduce the LFV component, and Fig. 3 A and B are diagrams showing the method of the present invention. FIG. 2 is a diagram showing the results of measurements of LFV components of tires. T is a tire, 2 is a road roll, 3 is a load cell, 4 is a measurement controller, 5 and 6 are servo amplifiers,
7, 8, 9, 10 are grinder operating mechanisms, 1
1 and 12 are grinding wheels, 13 is a load cell, 14 is a signal processing circuit, 15 and 16 are measurement terminals, and 17 is a measurement recorder.

Claims (1)

[Claims] 1. Rotate the tire in forward and reverse directions, measure each variation in the lateral force acting on the supporting surface during one rotation, then synthesize the measured lateral force variations and calculate the average lateral force. By determining the variation in the force and then averaging the variation in the average lateral force, the two areas on the circumference of the tire to be polished at both shoulder portions are determined, and then,
Within one of the determined areas, depending on the direction of the average lateral force, one shoulder portion thereof is polished to a predetermined depth depending on the variation of the average lateral force, 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 depending on the variation of the average lateral force, and the tire is polished. A method for correcting tire non-uniformity, characterized by reducing fluctuations in the generated lateral force.