WO2004065142A1

WO2004065142A1 - Tire, its forming method, device for reducing external magnetic field of tire, and vehicle mounted with that tire

Info

Publication number: WO2004065142A1
Application number: PCT/JP2003/016461
Authority: WO
Inventors: Masami Kikuchi; Tadashi Hagiwara
Original assignee: Bridgestone Corporation
Priority date: 2003-01-17
Filing date: 2003-12-22
Publication date: 2004-08-05
Also published as: JP4243249B2; JPWO2004065142A1; AU2003289480A1

Abstract

A tire having a steel belt arranged such that the strength of a magnetic field being formed at a point separated by 5 mm to the outside in the direction of a normal to the surface becomes 0.15 mT or less for all directions for all points on the surface of the tire, and formation of a magnetic field having an effect on the measurement of magnetic field can be prevented when the characteristics of the tire are determined by measuring a magnetic field being formed by magnet pieces pasted to the surface of the tire. A method for forming the tire, a device for reducing external magnetic field of tire being employed in the method for forming the tire, and a vehicle mounted with that tire are also provided.

Description

Description Tire, tire forming method, tire external magnetic field reduction device, and vehicle equipped with tire

The present invention relates to a tire having a belt formed of one or more belt layers on which steel cords are arranged and having a small magnetic field formed outside, a method of forming the tire, and a tire external magnetic field reduction device used in the method of forming the tire The present invention relates to a vehicle equipped with the tire. Background art

Tires provided with a belt comprising a belt layer in which steel cords are arranged are widely used. Then, such a tire forms a magnetic field that can be detected outside due to the magnetization remaining in the steel cord, as described in Japanese Patent Application Laid-Open No. 10-307145. The magnitude of the magnetic field is large enough to detect the magnetic field, calculate the tire rotation speed from the time change of the magnetic field, and estimate the traveling distance of the vehicle. By the way, in recent years, in order to estimate the friction coefficient directly from the force acting on the tire, a small piece magnet is attached to a predetermined portion of the tire, for example, a predetermined portion of the tread portion of the tire, and the magnetic field from the magnet changes the tread portion. The method of measuring the displacement of a tire by calculating the displacement of the tire and calculating the force acting on the tire from the displacement, and the method of attaching a small magnet to a predetermined part of the tire and using the magnetic field from the magnet that changes with temperature. Therefore, a method of detecting a temperature of a tire for detecting an abnormality in the temperature of the tire is being studied.

Naturally, in these methods, it is important to detect the magnetic field from the small piece magnet with high accuracy, and for that purpose, the magnetic field from other than the small piece magnet must be suppressed. As mentioned above, due to remanent magnetization of steel cord Therefore, it was difficult to achieve those methods because sufficient magnetic field detection accuracy could not be obtained due to the influence of the generated magnetic field.

The present invention has been made in view of such a problem. When a small magnet is attached to a tire and the magnetic field formed by the magnet is measured to determine the characteristics of the tire, the influence on the magnetic field measurement is obtained. It is an object of the present invention to provide a tire that does not form a magnetic field to be applied, a method of forming the tire, a tire external magnetic field reduction device, and a vehicle equipped with the tire. Disclosure of the invention

The present invention has been made to achieve the above object, and its gist configuration, operation and effects are described below.

(1) The present invention relates to a tire provided with a belt made up of one or more belt layers on which steel cords are arranged, wherein all points on the tire surface are 5 mm outward in the normal direction from each point. The tire has a magnetic field strength of 0.15 mT or less in any direction at a point separated from the tire.

According to the tire 1 of the present invention, with respect to all points on the tire surface, the strength of the magnetic field formed at a point separated by 5 mm on the outer side in the surface normal direction set at each point, in any direction Is less than 0.15 mT, which affects the magnetic field measurement when a small magnet is attached to the tire 1 and the magnetic field formed by the magnet is measured to determine the characteristics of the tire. Formation of such a magnetic field can be prevented.

(2) In the present invention, in (1), the belt is composed of a plurality of belt layers, and the steel cord of each belt layer is formed between two belt layers adjacently stacked with respect to the tire equatorial plane. In addition to arranging it in the opposite direction, the surface magnetic force of the steel cord is localized only at both ends, and the surface magnetic force at the end of the steel cord located on the same side in the tire width direction is the same in the same belt layer. Polar tires have two polarities, and two adjacent belt layers have different polarities. You.

(3) In the present invention, when forming the tire according to (1) or (2), the rod-shaped magnet is brought into contact with or close to the tire outer peripheral surface in a posture facing the tire width direction, and the posture of the rod-shaped magnet with respect to the tire rotation axis. When the basic operation is to rotate the outer periphery of the tire relative to the tire more than the tire circumference while keeping the tire constant, and to move the bar-shaped magnet away from the tire rotation axis, At some point until the use of the tire is completed, this basic operation is continuously performed a plurality of times to reduce the strength of the magnetic field formed outside the tire.

(4) In the present invention according to (3), in the basic operation, the rotation angle when the rod-shaped magnet is relatively rotated with respect to the tire corresponds to an extension length of the steel cord along the tire circumferential direction. This is a method for forming a tire having an angle equal to or more than the angle obtained by adding 360 degrees to the rotation angle.

(5) The present invention provides the method according to (3) or (4), wherein the tire is rotated by setting the tire on a tire balancer for measuring the balance of the tire by rotating the tire to perform the basic operation. It is a forming method.

(6) In the tire according to (3) or (4), after the tire mounted on the vehicle is separated from the ground, the tire is rotated while the tire is mounted on the vehicle to perform the basic operation. It is a forming method.

(7) The present invention relates to a device for reducing an external magnetic field of a sunset, which is used in the method for forming a tire according to any one of (3) to (6),

A tire external magnetic field reduction device comprising: a tire rotation driving means for gripping and rotating a tire; the rod-shaped magnet; and a magnet displacement driving means for separating the rod-shaped magnet stepwise outward in the tire radial direction with respect to the tire. is there.

(8) The present invention is a vehicle equipped with the tire according to (1) or (2). BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a meridional sectional view showing a tire according to an embodiment of the present invention. FIG. 2 is a plan developed view of a belt showing an arrangement of steel cords.

FIG. 3 is a schematic diagram showing the surface magnetic force distribution in the length direction of the steel cord.

FIG. 4 is a perspective view showing a tire external magnetic field reduction device.

FIG. 5 is a perspective view showing an arrangement of magnetic poles of a magnet, which is an enlarged view of a portion "A" in FIG. FIG. 6 is a trajectory diagram showing a trajectory of a magnet that moves relatively to a tire.

FIG. 7 is a perspective view showing the relative arrangement of a steel cord and a magnet in an experiment in which the magnetic force of a single steel cord is changed.

FIG. 8 is a graph showing changes in the surface magnetic force of the steel cord in the experiment shown in FIG.

FIG. 9 is a graph of the change following FIG.

FIG. 10 is a perspective view showing another embodiment of the tire external magnetic field reduction device.

FIG. 11 is a graph showing a magnetic field formed by a conventional tire.

FIG. 12 is a graph showing a magnetic field formed by the tire of the example.

FIG. 13 is a graph showing a magnetic field formed by a conventional tire to which a magnet sheet is attached.

FIG. 14 is a graph showing a magnetic field formed by the tire of the example with the magnet sheet attached. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing the tire 1 of this embodiment in a meridian plane, and FIG. 2 is a developed plan view of a belt showing the arrangement of steel cords when the belt of the tire is viewed from the outside in the tire radial direction. It is. In FIG. 2, C represents the tire circumferential direction. The tire 1 has a belt 5 disposed on the tread portion 2, and the belt 5 has an inner belt layer 3 in which steel cords 13 are arranged and a steel cord 14 arranged. The outer belt layer 4 and the outer belt layer 4 are laminated in the tire radial direction, and both the steel cords 13 and 14 are inclined at an angle with respect to the tire equatorial plane E, but the direction of each inclination is the tire equator. The surfaces are arranged to be inclined in opposite directions to each other.

In both steel cords 13 and 14, the surface magnetic force is localized only at both ends, and at one tire width direction end W 1 of belt 5, steel cords 13 of inner belt layer 3 are formed. The surface magnetic force at the end portion has all N-polarity, while the surface magnetic force at the end portion of the steel cord 14 of the outer belt layer 4 has the S-polarity, and vice versa. In addition, at the other end W2 of the belt 5 in the tire width direction, the surface magnetic force at the end of the steel cord 13 has the polarity of the S pole, while the surface at the end of the steel cord 14 has All magnetic forces have N polarity.

Here, the surface magnetic force refers to the magnitude of the magnetic force detected on the outer surface of the steel cord, and refers to the density of lines of magnetic force radiated from the surface of the steel cord. Fig. 3 shows the distribution of surface magnetic force along the length direction of the steel cords 13 and 14 described above, the horizontal axis shows the position in the tire width direction, and the vertical axis shows the magnitude of the surface magnetic force. Fig. 3 (a) and Fig. 3 (b) show the surface magnetic force distribution of steel cord 13 and steel cord 14, respectively. The left end of the vertical axis indicates the position corresponding to the end Wl in the belt width direction, and the right end indicates the position corresponding to the end W2 in the belt width direction.

Since the surface magnetic force is localized only at both ends of the steel cords 13 and 14 arranged in such a magnetized manner, the portion that emits the magnetic field lines to the outside is limited to both ends, and In the tire radial direction immediately adjacent to the end of the steel cord 13 (14) arranged on one belt layer, the end of the steel cord 14 (13) arranged on the other belt layer must be Since these end portions are close to each other and have surface magnetic forces of different polarities, most of the magnetic lines of force extend between these end portions, greatly suppressing the magnetic lines of leakage to the outside. Thus, the magnetic field formed outside the evening can be greatly reduced. As described above, when a plurality of rod-shaped magnets having N and S poles at both ends, respectively, are connected in a ring shape by attracting the N and S poles, the magnetic field formed outside is almost the same. It is the same principle that it becomes almost zero.

In addition, since the magnetic field formed outside is small in the dinner 1 having such a configuration, a small magnet can be attached to the tire 1 and only the magnetic field from the small magnet can be detected with high sensitivity. Furthermore, since the tire 1 does not form a magnetic field outside, a large magnetic field exists inside the steel cord, and each magnetic field forms a magnetic path inside. It is possible to provide a high coercive force to an external magnetic field that is applied to the tire, for example, and to prevent the belt of the running tire from re-magnetizing the surface magnetic force due to the external magnetic field.

Next, a method of forming the tire 1 will be described. FIG. 4 is a perspective view showing a tire external magnetic field reduction device 20 used to form the tire 1. FIG. 5 is an enlarged view of a portion "A" in FIG. FIG. 5 is a perspective view showing a radiation mode in the same direction as FIG.

The tire external magnetic field reduction device 20 is also configured as a rotation drive portion of a tire balancer 25 that measures balance while rotating the tire 1, and a tire balance measurement rim 11 on which the tire 1 is mounted. A motor rotation driving means 23 for rotating the rim 11 by a motor and a drive, a rod-shaped magnet 21, and a magnet displacement driving means 24 for gradually displacing the rod-shaped magnet 21 radially outward of the tire 1 are provided. Equipped. Further, although not shown, the trajectory of the rod-shaped magnet 21 when the tire 1 and the rod-shaped magnet 21 are relatively moved is controlled by cooperating the tire rotation driving means 23 and the magnet displacement driving means 24. It also has relative movement control means. The rod-shaped magnet 21 is placed in a posture parallel to the rotation axis of the tire 1 and in such a position that the magnetic field lines radiated between the N pole and the S pole extend in the equatorial plane and intersect the belt 5. It is arranged to be in contact with or close to the outer peripheral surface of 1. In addition, since the tire external magnetic field reduction device 20 is configured to also serve as the rotation driving portion of the tire balancer 25, the cost for reducing the tire external magnetic field can be suppressed. FIG. 6 is a trajectory diagram showing the trajectory of the magnet 21 relatively moving with respect to the tire 1 as viewed from the tire axial direction with the tire stationary. That is, FIG. 6 shows the trajectory of the bar-shaped magnet 21 as viewed from a point on the rotating tire 1. With reference to FIG. 6, a method of forming the tire 1 using this device 20 will be described. First, the bar-shaped magnet 21 is disposed at a point S 1 separated from the outer peripheral surface of the tire 1 by d 1. Next, the rotation of tire 1 is started, and the rotation of tire 1 is stopped at point F 1 where tire 1 has turned an additional 1 angle from one lap, and rod-shaped magnet 21 is displaced radially outward by distance d 2. To move to point S2. Then, the rotation of the tire 1 is restarted, and the rotation of the tire 1 is stopped at the point F2 where the tire 1 has turned an extra angle of 2 from the one lap, and the rod-shaped magnet 21 is displaced radially outward by the distance d2. To point S3. Similarly, the rod-shaped magnet 21 is further moved in the order of F3, S4, F4, S5, and F5, and then the tire is taken out of the device 20.

Thus, the method of forming the tire is as follows. When the tire 1 starts rotating, the tire 1 stops rotating at a point where the tire 1 has turned an additional angle beyond a single rotation, and the rod-shaped magnet 21 is moved radially outward by a predetermined distance. It is characterized in that the basic operation is performed several times, and the basic operation is performed several times in the example shown in Fig. 6, and the steel cord having the surface magnetic force distribution shown in Fig. 3 by this continuous operation A tire 1 having 13 and 14 can be formed.

Next, the principle of the tire forming method will be described. FIGS. 7 to 9 are diagrams for explaining an experiment in which a magnet M is arranged near one steel cord SC and the magnet M is displaced from one end to the other end in the length direction of the steel cord SC. Fig. 7 is a perspective view showing the relative arrangement of the steel cord SC and the magnet M. Figs. 8 and 9 show the surface magnetic force distribution that changes depending on the position of the magnet M. The horizontal axis shows the length of the steel cord SC. FIG. 9 is a graph showing the magnitude of surface magnetic force in which the direction position is taken and the vertical axis represents the N pole as positive and the S pole as negative, for each position of the magnet M in order. In this experiment, the magnet M was moved from one end A to the other end B of the steel cord SC, and the magnetic pole S was placed on the end A side. Displace while maintaining the posture where N is located on the end B side.

Fig. 7 (a) shows the surface magnetic force distribution of the steel cord SC in the initial state where the magnet M is kept at a point P0 far away from the steel cord SC. In this state, the surface magnetic force is S pole at the end A. It is assumed that the end B has an N pole, and portions other than these ends are magnetized so that no surface magnetic force exists.

Fig. 7 (b), Fig. 7 (c), Fig. 8 (a), Fig. 8 (b) and Fig. 8 (c) show the magnet M at points P1, P2, P3, P4 and This shows the distribution of the surface magnetic force of the steel cord SC when the steel cord SC is moved to P5 in order.The operation of moving this magnet temporarily resets the surface magnetic force remaining on the steel cord SC, and sets a new peak of the surface magnetic force to the steel cord SC. It is formed along the length direction of the SC and is sequentially moved with the movement of the magnet M. In this way, in the final state where the magnet M is withdrawn to the position P5 sufficiently separated from the steel cord SC. The surface magnetic force of the N pole and the S pole can be formed only near the end A and the end B, respectively.

Referring to the experimental results, the basic operation shown in FIG. 6 described above is described. When the bar-shaped magnet 21 is relatively moved from one circumferential direction of the tire 1 to the other, this operation is For both the cord 13 and the steel cord 14, this means moving the magnet M along the length of the cord from one circumferential direction to the other, and as a result, based on the experimental results described above. The surface magnetic force of the parts other than both ends of the steel cords 13 and 14 is set to almost zero, and the same is applied to the one end in the circumferential direction for both the cord 13 and the cord 14. It forms the surface magnetic force of one pole, for example, the N pole, and the same other pole, for example, the surface magnetic force of the S pole, at the end on the other side in the circumferential direction.

And, since the steel cords 13 and 14 are arranged so as to be inclined in the opposite direction with respect to the tire equatorial plane E, this is not remarkable, and at one end W 1 of the belt 5 in the tire width direction. Indicates that the surface magnetic force at the end of the steel cord 13 of the inner belt layer 3 has N-polarity, but the steel cord 14 of the outer belt layer 4 The surface magnetic force at the end of the belt has the polarity of the S pole. Conversely, at the other end W2 of the belt 5 in the tire width direction, the surface magnetic force at the end of the steel cord 13 is This means that all forces have S polarity, but the surface magnetic force at the end of steel cord 14 has all N polarity.

However, the relative movement of the bar-shaped magnet 21 along the outer peripheral surface of the tire 1 is different from the experiment of moving the magnet M along one steel cord SC as described above. 4 is formed endless, so that when the bar-shaped magnet 21 is stopped at the point F1 in FIG. 6, the steel codes 13 and 1 located opposite the bar-shaped magnet 21 at the point F1 In Fig. 4, the magnet 21 is located near the center of the cord and has a surface magnetic force distribution as shown in Fig. 8 (b), Fig. 8 (c), Fig. 9 (a), or Fig. 9 (b). Therefore, only the belt portion at the circumferential position facing the bar-shaped magnet 21 has a peak of the surface magnetic force even if it is not the end portion of the steel cord. The basic operation is performed a plurality of times in order to gradually reduce the peak of the remaining surface magnetic force in this manner, and the basic operation is performed at a circumferential position facing the bar-shaped magnet 21 by the plurality of basic operations. The operation of resetting the surface magnetic force once and forming a weaker surface magnetic force part at another circumferential position than before is repeated, and in the final operation, only a sufficiently small surface magnetic force peak remains Belt 5 can be formed. The above is the principle of the method of forming a tire for reducing the magnetic field formed outside the tire, and the tire 1 can be formed extremely easily. Here, the angles al, α2,... Shown in FIG. 6 are preferably rotation angles corresponding to the lengths of the steel cords 13 and 14 extending along the tire circumferential direction. This makes it possible to move the steel cords 13 and 14 around the entire circumference between both ends in the longitudinal direction, and to reset the residual surface magnetic force without fail.

Also, after being moved outward in the radial direction, the magnet 21 applies a magnetic field that is large enough to reset the surface magnetic force remaining on the steel cords 13 and 14 up to that point. W

The final separation distance of the magnet 21 from the tire 1 must be set so that the surface magnetic force of the magnet 21 remaining on the belt 5 is sufficiently small. Then, it is necessary to determine the distances d 2, d 3,... When the rod-shaped magnet 21 is displaced radially outward stepwise.

In the method described above, when the magnet 21 is displaced away from the tire 1, the rotation of the tire 1 is temporarily stopped, but the rotation is continuously performed over a plurality of basic operations without temporarily stopping the tire 1. The same effect can be obtained. Further, the length of the magnet is preferably equal to or greater than the width direction of the tire, whereby the surface magnetic force can be reliably adjusted to the end of the steel cord.

FIG. 10 is a perspective view showing a tire external magnetic force reduction device 30 of another embodiment. The device 30 reduces the magnetic field formed by the tire 1 outside without removing the tire 1 mounted on the vehicle 15 from the vehicle 15. Or, a chuck 3 2 for gripping a rim for mounting the tire 1, a tire rotation driving means 33 for rotating the chuck 3 2, a rod-shaped magnet 31, and a magnet displacement driving means 3 4 for displacing the rod-shaped magnet 31 outward in the tire radial direction. Although not shown, relative movement control means for controlling the trajectory of the bar-shaped magnet 21 when the tire 1 and the bar-shaped magnet 31 are relatively moved is provided.

The details of the function of each means and the method of forming a tire using this apparatus 30 are already the same as those described for the apparatus 20 shown in FIG. The point that the device 30 of this embodiment becomes the device 20 is, first, to form the tire 1 in which the magnetic field formed outside is suppressed while the tire 1 is mounted on the vehicle 15. Before starting the basic operation of the vehicle, it is necessary to lift the tire off the ground by jacking up the vehicle.Second, it is difficult to fix the vehicle 15 in a predetermined position. It is necessary to set the tire rotation driving means 33 and the magnet displacement driving means 34 in accordance with the arrangement of the tires 15 and the respective tires 1.Therefore, these means must be configured to be portable. It is a point.

Since the device 30 can reduce the external magnetic field generated by the tire mounted on the vehicle 15 while the tire is mounted on the vehicle 15, the processing can be easily performed even on the tire 1 that is magnetized during traveling. Example

By performing the above-mentioned basic operations continuously on a conventional tire (conventional example), tires (examples) of the present embodiment shown in FIG. 1 are formed, and the external magnetic field formed by these tires is measured. Compared. Figs. 11 and 12 show the external magnetic field formed by the tires of the conventional example and the example for the tire circumferential direction component, the tire radial direction component, and the tire width direction component, respectively, measured over one round in the tire circumferential direction. The graph shows the strength of the magnetic field represented by the magnetic flux density on the vertical axis, and the circumferential position of the tire on the horizontal axis. This measurement was performed using a Gauss meter that measures the magnetic field using a Hall element, and the magnetic field was detected at a position 5 mm away from the tire outer circumferential surface on the tire equator.

The relevant key specifications of these tires are as follows.

Tire size: 1 95/60 R 15

Number of belt layers: 2

Belt layer width (mm): Inner layer 1 52, Outer layer 140

Angle of inclination of steel cord with respect to the equatorial plane (degree): Inner layer 24, outer layer 24 Number of steel cords to be driven (strands / 50 mm): inner layer 34, outer layer 50 Also used when forming tires of Examples The magnet strength was 80 mT at the center surface, the tire rotation angle was 720 degrees in all basic operations, the number of basic operations was three times, and the distance to keep the magnet away each time was 5 mm.

As is evident from Figs. 11 and 12, the conventional tire generates a magnetic field component that has a maximum of 0.5 mT or more by repeating the above basic operation continuously. W

Was about 0.1 mT or less.

Figures 13 and 14 show small pieces with different polarities on the inner and outer peripheral surfaces of the tire at the four points on the circumference and the equatorial plane of the tire, respectively. The external magnetic field formed by these tires when the magnets were attached was measured over the entire circumference by a Gauss meter placed 5 mm radially outward from the tire's equatorial plane and from the outer peripheral surface of the tire. 12 is a graph showing the strength of the magnetic field on the vertical axis and the circumferential position of the tire on the horizontal axis, similarly to FIGS. The attached small piece magnet has a size of 30 mm square, and is a pound magnet formed by dispersing ferrite in a rubber composition.

As is clear from FIGS. 13 and 14, the magnetic field formed by the small piece magnet alone is about 0.3 mT, and in the conventional tire, the maximum magnetic field component caused by the belt 5 is 0. Since it is 5 mT or more, it is difficult to distinguish the magnetic field formed by the small-piece magnet from the magnetic field caused by the steel cord when the small-piece magnet is attached to the tire of the conventional example. Since it is suppressed, only the magnetic field generated by the small piece magnet can be extracted. Industrial applicability

As is clear from the above description, since the tire of the present invention does not form a magnetic field outside, the characteristics of the tire determined by pasting a small magnet and measuring the magnetic field formed by this magnet, It can be used for detecting the running state of a vehicle derived from characteristics.

Claims

The scope of the claims

1. In a sunset with a belt consisting of one or more belt layers with steel cords arranged, all points on the tire surface shall be separated from each point by 5 mm in the direction normal to each point. A tire having a magnetic field strength of 0.15 mT or less in any direction.

2) The belt is composed of a plurality of belt layers, and the steel cords of each belt layer are arranged so that two adjacent belt layers are inclined in the opposite direction to the tire equatorial plane. The surface magnetic force of the steel cord is localized only at both ends, and the surface magnetic force at the end of the steel cord located on the same side in the tire width direction has the same polarity in the same belt layer, and is laminated adjacently 2. The tire according to claim 1, wherein the two belt layers have different polarities.

3. When forming the tire described in claim 1 or 2, the rod-shaped magnet is brought into contact with or close to the tire outer peripheral surface in a posture facing the tire width direction, and the rod-shaped magnet is rotated with respect to the tire rotation axis. When the basic operation consists of rotating the outer periphery of the tire relative to the tire more than the tire circumference while maintaining the tire position constant, and then moving the bar-shaped magnet away from the tire rotation axis, the tire is vulcanized. At some point after the completion of the use of the tire, the basic operation is performed a plurality of times in succession to reduce the strength of the magnetic field formed outside the tire.

4. In the above basic operation, the rotation angle when the bar-shaped magnet is rotated relative to the tire is calculated by adding 360 degrees to the rotation angle corresponding to the length of the steel cord extending along the tire circumferential direction. 4. The method for forming a tire according to claim 3, wherein the method is as described above.

5. The tire according to claim 3 or 4, which performs the basic operation by rotating the tire by setting the tire on a tire balancer for measuring the balance of the tire by rotating the tire. Forming method.

6. After the tire mounted on the vehicle was separated from the ground, the tire was mounted on the vehicle. The tire forming method according to claim 3 or 4, wherein the basic operation is performed by rotating the tire as it is.

7. A device for reducing an external magnetic field of a tire, which is used in the method for forming a tire according to any one of claims 3 to 6,

A tire external magnetic field reduction device comprising: tire rotation driving means for gripping and rotating a tire; said rod-shaped magnet; and magnet displacement driving means for separating the rod-shaped magnet stepwise radially outward from the tire in the tire radial direction.

8. A vehicle equipped with the tire according to claim 1 or 2.