JP2002195916A - Device for detecting displacement of elastic wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect the displacement between a wheel disk and a rim in an elastic wheel formed by coupling the wheel disk and the rim through an elastic body. SOLUTION: A permanent magnet 21 is allocated at the side of the rim 14 of the elastic wheel 10, and magnetic detecting elements 22X, 22Y that detect components of magnetic field crossing perpendicular to each other generated by the permanent magnet 21 respectively, are allocated at the side of the wheel disk 12. The magnetic field is detected, and then the displacements in the axial and circumferential directions of tire or the displacements in the axial and radial directions of tire are separately detected using a map 20 being generated beforehand and representing the relationship between outputs of the magnetic detecting elements 22X, 22Y in the case the displacement between the wheel disk 12 and the rim 14 occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting a displacement between a disc and a rim of an elastic wheel in which a wheel disc and a rim are connected via an elastic body.

[0002]

2. Description of the Related Art Conventionally, in order to improve the running stability of an automobile, it has been required to accurately estimate a friction coefficient between a tire and a road surface (road surface friction coefficient) or a road surface state and feed it back to vehicle control. In other words, if the road surface friction coefficient and the road surface state can be estimated in advance, for example, the ABS or the like is required before the danger avoidance operation such as braking / driving or steering is performed.
Advanced control of the brake and the like can be performed, and safety can be further improved. In addition, the driver can perform an early deceleration operation simply by informing the driver of the danger of the road surface condition during traveling, and a reduction in accidents can be expected. As a method of estimating the road surface friction coefficient, for example, a method of measuring and estimating a vibration transmission characteristic between an unsprung and a sprung state of a vehicle has been proposed (Japanese Patent Application Laid-Open No. H11-94661). Specifically, the unsprung acceleration is vertical acceleration of the wheel, and the resonance frequency f _r of the transfer function between the sprung acceleration is the acceleration of the vehicle body in the vertical direction, the gain ratio (G _p /
G ₀ ) and the vehicle speed V are measured, and the road surface friction coefficient, the resonance frequency _fr, and the gain ratio (G _p /
From the relationship with G ₀ ), the road surface friction coefficient is estimated.

On the other hand, in order to improve the riding comfort of a vehicle,
Various methods have been proposed for suppressing vibration transmitted from the steering shaft to the steering wheel. As an example, an elastic body is fixed to the side corners of the wheel cover, and this elastic body is frictionally engaged with the spokes of the steering wheel body, or a seat made of the elastic body is tightened on the inner surface of the rim. There is a method of holding and mounting (for example, JP-A-10-181611, JP-A-2000-280705). However,
These methods could not sufficiently achieve the above object. Therefore, in recent years, as shown in FIG.
And a rim 14 for mounting the tire body 13 with the elastic member 1
T with an elastic wheel 10 connected via
Is being actively developed.

[0004]

In the tire T provided with such an elastic wheel 10, the tire body 13 is located from the road surface.
When a stress acts on the tire, the deformation of the elastic member 15 causes axial, circumferential and radial displacement of the tire and circumferential and radial twist between the wheel disc 12 and the rim 14. Therefore, the structure is such that the stress is not directly transmitted to the steering shaft 11. Therefore, it is difficult to accurately grasp the tire-road surface characteristics such as the braking force, the driving force, the lateral force, and the above-described road surface friction coefficient. Therefore, these characteristics can be effectively used for vehicle running control. could not. Therefore, development of a technique for detecting and grasping the behavior of such an elastic wheel 10 is desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the conventional problems, and it is an object of the present invention to accurately detect a displacement between a wheel disc and a rim of an elastic wheel in which a wheel disc and a rim are connected via an elastic body. It is an object of the present invention to provide an elastic wheel displacement detecting device which can be used.

[0006]

According to a first aspect of the present invention, there is provided an elastic wheel displacement detecting device, comprising: a permanent magnet disposed on a rim / wheel disc side; The first and second sensors respectively detect magnetic field components orthogonal to each other from the magnet.
And a map, which is prepared in advance, which shows the relationship between the output of the first magnetic detecting means and the output of the second magnetic detecting means when the wheel disc and the rim are displaced. Tire axial displacement and tire circumferential displacement,
Alternatively, based on the outputs of the two magnetic detecting means, which depend on the displacement in two directions, the displacement in the tire axial direction and the displacement in the tire radial direction, the displacement amount in the tire axial direction and the displacement amount in the tire circumferential direction, or the displacement in the tire axial direction Separation detecting means for separating and detecting the amount and the amount of displacement in the tire radial direction.

According to a second aspect of the present invention, the magnetic field component from the magnet due to the displacement between the wheel disk and the rim, detected by the two magnetic detecting means, is generated in the tire axial direction and the tire circumferential direction. In order for the magnet to have only two directions, the magnet is a magnet whose magnetic pole surface is perpendicular to the tire axis direction and extends in the tire radial direction, and the direction of the magnetic field detected by the first magnetic detecting means is the tire. The two magnetic detectors are arranged so that the direction of the magnetic field detected by the second magnetic detector is in the tire circumferential direction in the axial direction. In addition, in the elastic wheel displacement detection device according to claim 3, the magnet component is configured so that the magnetic field components detected by the two magnetic detection units are only in two directions, a tire axial direction and a tire radial direction. Is a magnet whose magnetic pole surface is perpendicular to the tire axial direction and extends in the tire circumferential direction, and the direction of the magnetic field detected by the first magnetic detecting means is in the axial direction of the tire, and the second magnetic detecting means is The two magnetic detecting means are arranged so that the direction of the magnetic field detected by the magnetic field detecting means is in the tire radial direction.

According to a fourth aspect of the present invention, there is provided an elastic wheel displacement detecting device for detecting a disturbance such as terrestrial magnetism at a location separated by a predetermined distance from the magnet and correcting outputs of the two magnetic detecting means. , And a magnetic detecting means for correction.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the present invention in which the wheel disc 12 to which the steering shaft 11 is connected and the rim 14 to which the tire body 13 is attached are connected to the elastic wheel 10 shown in FIG. FIG. 2 is a schematic diagram showing an example of an installation state of a magnet and a magnetic detection element in the elastic wheel displacement detecting device, and FIG. 2 is a block diagram showing a configuration of the displacement detecting device. In FIG. 1, reference numeral 20 denotes a first magnetic pole surface (here, an N pole) disposed on the rim 14 side and extending in a tire axial direction (X direction) and extending in a tire radial direction (Z direction).
And the magnetism detecting element 22X attached to the wheel disc 12 and arranged so that the direction of the magnetic field to be detected is the axial direction of the tire, and the direction of the magnetic field to be detected is the circumferential direction of the tire (Y direction). ), A first displacement detection means including a two-axis detection sensor (hereinafter, referred to as a circumferential sensor) 22 having a magnetic detection element 22Y arranged to be 3
Numeral 0 denotes a second magnet 3 disposed on the rim 14 side and having a magnetic pole surface (N pole) perpendicular to the tire axial direction and extending in the tire circumferential direction.
1 and a magnetic detection element 32X attached to the wheel disk 12 and arranged so that the direction of the magnetic field to be detected is in the axial direction of the tire, and is arranged so that the direction of the magnetic field to be detected is in the radial direction of the tire. A two-axis detection sensor (hereinafter referred to as a diameter sensor) 32 having a magnetic detection element 32Y provided therein.
And a second displacement detecting means comprising: The directions of the magnets 21 and 31 and the sensors 22 and 32 correspond to the states when the magnets 21 and 31 and the sensors 22 and 32 are attached to the elastic wheel 10, namely,
This is a direction in a state where no displacement or twist between the wheel disc 12 and the rim 14 occurs.

As shown in FIG. 2, the displacement detecting device for the elastic wheel includes the above-described first and second magnets 21 and 31 and two two-axis detection sensors (circumferential sensor 22 and diameter sensor 32).
From the outputs of the sensors 22 and 32,
By subtracting a disturbance magnetic field such as terrestrial magnetism detected by the correction magnetic detecting means 40S (not shown in FIG. 1) provided at a place where the magnetic force from the magnets 21 and 31 can be ignored at a predetermined distance from 31 The outputs of the sensors 22 and 32, that is, the magnetic detection elements 22X and 22Y and the magnetic detection element 3
The output correction means 40 for correcting the outputs of 2X and 32Y and the relationship between the output of the magnetic detection element 22X and the output of the magnetic detection element 22Y when the space between the wheel disk 12 and the rim 14 is displaced are prepared. Axis / circumference separating means 51 for calculating the distance and direction (inclination) of the corrected outputs of the magnetic detection elements 22X and 22Y from the origin (zero displacement point) on the map M20 shown, and the tire axis Detecting element 32X due to the displacement in the tire direction and the displacement in the tire radial direction.
Axis / diameter separating means 52 for calculating the distance from the origin and the inclination direction of the corrected outputs of the magnetic detection elements 32X and 32Y on a map M30 showing the relationship between the outputs of 32Y.
And a displacement converting means 53 for converting the calculated distance and inclination into the amount of displacement in each direction of the tire. The output of each of the corrected sensors 22 and 32 is used in the tire axial direction, tire circumferential direction and tire direction. And a three-direction separation detecting means 50 for calculating the amount of displacement in the radial direction.

Next, a method of detecting the displacement of the elastic wheel 10 will be described with reference to the flowchart of FIG. Here, a case will be described in which the circumferential sensor 22 is used to calculate the amount of displacement in each of the tire axial direction and the tire circumferential direction. First, the magnetic detection element 22 of the circumference sensor 22
The output based on the magnetic field from the first magnet 21 detected by X, 22Y is sent to the correction means 40 (step S10). In the output correction means 40, the magnetic detection element 22
The respective outputs are corrected by subtracting a disturbance magnetic field such as terrestrial magnetism detected by the magnetic detection means for correction 40S from the outputs of X and 22Y (step S12), and sent to the shaft / circumference separating means 51.

During traveling, a stress is applied to the tire T from a road surface or the like, causing a displacement between the wheel disc 12 and the rim 14. Thus, the magnitude and direction of the magnetic field acting on the magnetic detection elements 22X and 22Y change, and the outputs of the magnetic detection elements 22X and 22Y change accordingly. FIG. 4 shows a pre-made wheel disc 12.
The magnetic detection element 22 when the distance between the
A map M20 indicating the relationship between the output of the X and the output of the magnetic detection element 22Y includes, for example, the wheel disk 12 and the rim 1
In the case where the gap between the four elements is displaced only in the circumferential direction (Y direction), the outputs of the magnetic sensing elements 22X and 22Y change respectively, but the changes in the outputs are not independent of each other and are constant as shown by the thick solid line in FIG. Change while maintaining relationships. When the distance between the wheel disk 12 and the rim 14 is displaced only in the axial direction, the outputs of the magnetic detection elements 22X and 22Y change on a curve as shown by a thick broken line in FIG. On the other hand, when the wheel disc 12 and the rim 14 are displaced only in the radial direction, the first magnet 21 is a magnet extending in the tire radial direction. Neither the component in the tire axial direction (X direction) nor the component in the tire circumferential direction (Y direction) change. Therefore, the outputs of the magnetic detection elements 22X and 22Y change only due to the displacement in the tire axial direction and the displacement in the tire circumferential direction, and change as shown in the map M20. Using the map M20, the displacement in the tire axial direction and the displacement in the tire circumferential direction can be separately detected.

The shaft / circumference separating means 51 writes the corrected changes in the outputs of the magnetic detection elements 22X and 22Y on the map M20, and outputs the distances and directions (from the origin) of the outputs of the magnetic detection elements 22X and 22Y from the origin. Is calculated (step S14), and this is sent to the displacement conversion means 53. The displacement conversion means 53 calculates the amount of displacement in the tire axial direction from the calculated distance (step S16), and calculates the amount of displacement in the tire circumferential direction from the inclination (step S16).
18). More specifically, as shown in FIG. 5, the relationship between the inclination and the tire circumferential displacement is obtained by using a curve group for each axial displacement, or an approximate expression representing the relationship between the tilt and the tire circumferential displacement is obtained. Prepare and obtain the approximate expression by substituting the gradient. Similarly, using the diameter sensor 32,
The respective displacement amounts in the tire axial direction and the tire circumferential direction can be calculated. That is, since the second magnet 31 is a magnet extending in the tire circumferential direction, when the wheel disc 12 and the rim 14 are displaced only in the circumferential direction,
Neither the axial component (X direction) nor the radial component (Z direction) of the tire changes with respect to the displacement. Therefore, the outputs of the magnetic detecting elements 32X and 32Y change only by the axial displacement and the radial displacement, and the magnetic detecting elements 32X and 32Y are prepared when the wheel disc 12 and the rim 14 are displaced in advance. Map M showing the relationship between the output of 32X and the output of magnetic detection element 32Y
30 on the map M30 by writing the distances and inclinations of the outputs of the magnetic detection elements 32X and 32Y corrected by the output correction means 40 from the origin and the map M30. The amount of displacement in the tire radial direction can be calculated from the inclination.

As described above, in the present embodiment, the first magnet 21 is disposed on the rim 14 side of the elastic wheel 10, and the magnetic detection elements 22X and 22Y are provided on the wheel disk 12 side. The circumferential sensor 22 is disposed, and the magnetic detection element is formed using a map M20 that is prepared in advance and shows the relationship between the outputs of the magnetic detection elements 22X and 22Y when the wheel disc 12 and the rim 14 are displaced. 2
Since the displacement in the tire axial direction and the displacement in the tire circumferential direction are detected separately from the outputs of 2X and 22Y, the displacement between the wheel disc and the rim can be accurately detected with a simple configuration. Further, the second magnet 31 is disposed on the rim 14 side, and the diameter sensor 22 including the magnetic detection elements 32X and 32Y is disposed on the wheel disk 12 side.
By detecting the magnetic field from the magnet, it is possible to detect displacement in the tire axial direction, displacement in the tire circumferential direction, and all displacements in the tire radial direction.

In the above embodiment, the magnets 21 and 31 are provided on the rim 14 side, and the magnetic detecting elements 22X, 22Y, 32X and 32Y are provided on the wheel disc 12 side. , 31 on the wheel disk side, and the magnetic detection elements 22X, 22Y, 32X, 32Y on the rim 14 side. Further, in the above example, the displacement detection device that separately detects the amount of displacement in the tire axial direction and the amount of displacement in the tire circumferential direction, and the amount of displacement in the tire axial direction and the amount of displacement in the tire radial direction have been described. A magnet extending in the axial direction is provided, and magnetic detecting means for detecting magnetic field components perpendicular to each other from the magnet are provided to separately detect the amount of displacement in the tire circumferential direction and the amount of displacement in the tire radial direction. It is also possible to constitute such a displacement detecting device. In the above example, the map M
20 and M30, the displacement of each direction of the tire is calculated by obtaining the distance and inclination from the origin of the output of the magnetic detection element 22X, 22Y or the magnetic detection element 32X, 32Y corrected by the output correction means 40. I tried to do
By creating the maps M20 and M30 in further detail, the tire axial direction, the tire circumferential direction, and the tire direction can be obtained directly from the outputs of the magnetic sensing elements 22X and 22Y or the outputs of the magnetic sensing elements 32X and 32Y or by using a well-known complementary method. The amount of displacement in the radial direction can be calculated. Further, the displacement detection device of the present example includes a first displacement detection unit 20 that detects a displacement amount in a tire axial direction and a tire circumferential direction, and a second displacement detection device that detects a displacement amount in a tire axial direction and a tire radial direction. With the means 30, the three displacement amounts in the tire axial direction, the circumferential direction and the radial direction are simultaneously detected. However, if necessary, only one of the displacement detecting means 20 and 30 is used. May be attached.

[0016]

As described above, according to the present invention,
A permanent magnet is provided on the rim side of the elastic wheel, and first and second magnetic detecting means for detecting magnetic field components orthogonal to each other from the magnet are provided on the wheel disk side, and the magnetic field from the magnet is provided. And using the previously prepared map showing the relationship between the outputs of the first and second magnetic detecting means when the wheel disc and the rim are displaced, the displacement in the tire axial direction and the tire Since the displacement amount in the tire axial direction and the displacement amount in the tire circumferential direction or the tire radial direction are separated from the outputs of the two magnetic detecting means depending on both the circumferential direction and the radial displacement of the tire,
The displacement between the wheel disc and the rim can be accurately detected.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of an installation state of a magnet and a magnetic detection element of a displacement detection device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a displacement detection device.

FIG. 3 is a flowchart showing a method for detecting a displacement of an elastic wheel according to the present embodiment.

FIG. 4 is a map showing the relationship between the outputs of the magnetic detection means when the wheel disc and the rim are displaced.

FIG. 5 is a diagram showing the relationship between the inclination on the map and the amount of circumferential displacement.

FIG. 6 is a schematic view of a tire provided with an elastic wheel.

[Explanation of symbols]

10 elastic wheel, 11 steering shaft, 1
2 wheel disc, 13 tire body, 14 rim, 15 elastic member, 20 first displacement detecting means, 21
1st magnet, 22 circumference sensor, 22X, 22Y magnetic detecting element, 30 second displacement detecting means, 31 first magnet, 32 diameter sensor, 32X, 32Y magnetic detecting element,
40 output correction means, 40S magnetic detection means for correction,
40R position sensor, 50 3-way separation detecting means, 51
Shaft / circumference separation means, 52 axis / diameter separation means, 53 displacement conversion means, 20M, 30M map, T tire.

Claims (4)

[Claims] A permanent magnet disposed on the rim / wheel disc side of an elastic wheel having a wheel disc and a rim connected via an elastic body;
First and second magnetic detecting means disposed near the magnet on the rim side and detecting magnetic field components perpendicular to each other from the magnet, respectively, and a gap between the wheel disk and the rim prepared in advance is displaced. At this time, using the map showing the relationship between the output of the first magnetic detecting means and the output of the second magnetic detecting means, the displacement amount in the tire axial direction and the tire circumference A displacement detecting device for an elastic wheel, comprising: separation detecting means for separately detecting a displacement in a tire direction or a displacement in a tire axial direction and a displacement in a tire radial direction. 2. The magnet according to claim 1, wherein the magnet is a magnet whose magnetic pole surface is perpendicular to the tire axial direction and extends in the tire radial direction, and the direction of the magnetic field detected by the first magnetic detecting means is in the axial direction of the tire. The displacement detecting device for an elastic wheel according to claim 1, wherein the two magnetic detecting means are arranged so that a direction of a magnetic field detected by the second magnetic detecting means is in a tire circumferential direction. 3. The magnet according to claim 1, wherein the magnet is a magnet whose magnetic pole surface is perpendicular to the tire axial direction and extends in the tire circumferential direction, and the direction of the magnetic field detected by the first magnetic detecting means is in the tire axial direction. 3. The two magnetic detecting means are arranged so that the direction of the magnetic field detected by the second magnetic detecting means is in the tire radial direction.
4. The displacement detection device for an elastic wheel according to claim 1. 4. A displacement detecting device for an elastic wheel according to claim 1, further comprising a magnetic detecting means for correction provided at a position separated by a predetermined distance from said magnet. .