JP2504982B2 - Wheel alignment measurement method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring wheel alignment such as toe-in and camber of wheels arranged on a vehicle.

(Prior Art) In a vehicle, it is extremely important that the wheel alignment, which directly affects the running stability, is properly adjusted. Wheel alignment is generally considered to include each element such as the toe-in, camber, caster, etc.When inspecting and servicing the vehicle, each of these elements should be measured quickly and surely, and according to the measurement results. Accurate adjustments need to be made.

Measuring the toe-in amount of the wheel alignment is
For example, as described in Japanese Patent Application Laid-Open No. 57-100307, generally, on both sides of the vehicle to be inspected in the width direction, two reference lines facing the tire side surface of the wheel with a predetermined separation distance are set. This is performed by detecting the distance between the reference line and the tire side surface of the wheel that is opposite to the reference line. Then, when there is a difference between the toe-in amount measured in this way and the preset proper toe-in amount, toe-in adjustment is performed on the wheels, and then the toe-in amount is measured again. . Then, the measurement of the toe-in amount and the toe-in adjustment according to the measurement result are repeated until the measured toe-in amount takes an appropriate value.

(Problems to be Solved by the Invention) When measuring the toe-in amount as described above, an error in the accuracy of mounting the wheel on the axle, which is included in the distance between the detected reference line and the side surface of the tire of the wheel, is included. Or, in order to reduce the error due to the deformation of the tire and improve the accuracy of the measured toe-in amount, the wheel is normally rotated once while the distance between the reference line and the tire side of the wheel is continuously changed. Then, the work for detecting the average value is performed.

For this reason, as described above, when the measurement of the toe-in amount and the toe-in adjustment according to the measurement result are repeated until the measured toe-in amount takes an appropriate value, the wheel is reset once every time the toe-in amount is measured. It is necessary to rotate and find the average value of the distance between the reference line and the tire side of the wheel,
As a result, there is an inconvenience that the time required to measure the toe-in amount is lengthened.

In view of such a point, according to the present invention, it is possible to perform the wheel alignment measurement after the alignment adjustment for the wheel is performed without rotating the wheel once, and as a result, it is possible to shorten the measurement time. It is intended to provide a method for measuring the adjusted wheel alignment.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the wheel alignment measuring method according to the present invention rotates a wheel, and a specific portion of a tire side surface arranged on the wheel makes one rotation. Stores the runout characteristics of the tire side surface with respect to the reference line, detects the distance from the reference line to the measurement site on the tire side surface after alignment adjustment for the wheel that is performed after storing the runout characteristics, and compares the measurement site with the specific site. The position is detected, the detected relative position, the shake amount of the measurement site with respect to the reference line is obtained by making it correspond to the stored shake characteristic, and based on this shake amount,
The distance from the detected reference line to the measurement site is corrected to obtain the corrected distance, and the wheel alignment amount is calculated based on the corrected distance.

(Operation) In the wheel alignment measuring method according to the present invention as described above, after the alignment adjustment with respect to the wheels is performed, the relative position of the measured portion with respect to the specific portion on the tire side surface is detected, and the detected relative position is detected. Is associated with the shake characteristic stored before the alignment adjustment is performed, so that the shake amount of the measurement site on the tire side surface with respect to the reference line is detected. Then, the distance from the reference line to the measurement site is corrected based on the shake amount, and the wheel alignment amount is calculated based on the corrected distance from the reference line to the measurement site.

Therefore, after the alignment adjustment, by detecting the distance from the reference line to any measurement site on the tire side surface, the error in the accuracy of mounting the wheel on the axle and the error associated with the deformation of the tire are corrected, Since the proper alignment amount is calculated, it is not necessary to rotate the wheel once for each measurement, and the time required for measuring the wheel alignment is significantly shortened.

(Example) Hereinafter, the Example of this invention is described with reference to drawings.

FIG. 1 schematically shows a toe-in measuring device used for carrying out an example of a wheel alignment measuring method according to the present invention. In FIG. 1, front wheels 2R and 2L arranged on a vehicle body (not shown) have a pair of rollers 4 extending in the vehicle width direction so that the toe-in amount can be measured.
One of the pair of rollers 4 is placed on the top of the roller 4 and is driven to rotate by a stepping motor 6.

Valves 18 for injecting air in the front wheels 2R and 2L respectively
Plate-like members 8R and 8L each having an engaging hole 9 formed in the central portion are arranged at positions facing the side surface of the tire where R and 18L are arranged. In the dowel 9,
Cams 12 fixed to the output shafts of the motors 10R and 10L are engaged. Therefore, the plate members 8R and 8L are
According to the rotation of the cam 12 due to the operation of R and 10L, the front wheel 2R and 2L can be moved to the left and right along the radial direction thereof, respectively.

At the position facing the tire side surface of the front wheel 2R in the plate-shaped member 8R, optical sensors 14R and 15R and optical sensors 16R and 17R for detecting the distance to the tire side surface of the front wheel 2R, which are respectively opposed to each other, are respectively, An optical sensor 20R that is arranged in pairs and that further detects the valve 18R arranged on the front wheel 2R
Is arranged. And these optical sensors 14R, 15R, 16R,
The tips of 17R and 20R are arranged on a straight line, and the straight line is the reference line Or. On the other hand, at the position facing the tire side surface of the front wheel 2L in the plate-shaped member 8L, the optical sensors 14L and 15L and the optical sensors 16L and 17L for detecting the distance to the tire side surface of the front wheel 2L that are respectively opposed to each other, Respectively,
Optical sensors 20L that are arranged in pairs and that detect the valves 18L arranged on the front wheels 2L are further arranged. The tip ends of the optical sensors 14L, 15L, 16L, 17L, and 20L are arranged on a straight line, and the straight line is the reference line Ol.

Then, in measuring the toe-in amounts of the front wheels 2R and 2L, the above-mentioned toe-in measuring device is supposed to perform the following operation in accordance with the wheel alignment measuring method according to the present invention. First, with the optical sensors 14R to 17R, the distance to the tire side surface of the front wheel 2R in a stationary state.
The a, b, c and d are detected, and the analog outputs Va, V from the optical sensors 14R to 17R take the levels according to the distances a to d, respectively.
b, Vc and Vd are obtained. The analog outputs Va to Vd are respectively supplied to the analog / digital converter (A / D
Conversion unit) Digital data Da, D at 22, 23, 24 and 25
After being converted into b, Dc and Dd, it is supplied to the controller 50. Along with this, the optical sensors 14L to 17L are used to measure the distance e, f, g to the tire side surface of the front wheel 2L in a stationary state.
And h are detected, and the analog output takes a level corresponding to the detected distances e to h from the optical sensors 14L to 17L, respectively.
Ve, Vf, Vg, and Vh are made available. Such analog outputs Ve to Vh are also converted into digital data De, Df, Dg and Dh in the A / D converters 28, 28, 30 and 31, respectively,
It is supplied to the controller 50.

The controller 50 calculates the difference between (Db-Da) and (Dc-Dd) from each of the digital data Da to Dd, supplies the control signal Sa corresponding to the difference to the drive unit 36, and the drive unit 36 , Operates the motor 10R according to the control signal Sa. Thereby,
The plate-shaped member 8R is moved, and along with it, the optical sensor 14
The positions of R to 17R can be changed. At that time, the optical sensor 14
The change in the position of R to 17R is set to have a small difference between (Db-Da) and (Dc-Dd) calculated in the controller 50, and the controller 50 uses (Db-Da) and (Dc-Dd). When the difference from Dd) becomes zero, the supply of the control signal Sa to the drive unit 36 is stopped. As a result, the positions of the optical sensors 14R to 17R are (Db-D
The difference between a) and (Dc-Dd) is set to zero.
Further, the controller 50 calculates the difference between (Df−De) and (Dg−Dh) from each of the digital data De to Dh, supplies the control signal Sb corresponding to the difference to the drive unit 38, and drives the drive unit. 38 is
The motor 10L is operated according to the control signal Sb. As a result, the plate member 8L is moved, and the positions of the optical sensors 14L to 17L are changed accordingly. At that time, the change in the positions of the optical sensors 14L to 17L is assumed to make the difference between (Df−De) and (Dg−Dh) calculated by the controller 50 small, and the controller 50 displays (Df−De). ) And (Dg-Dh) becomes zero, the supply of the control signal Sb to the drive unit 38 is stopped. As a result, the positions of the optical sensors 14L to 17L are (Df
The difference between −De) and (Dg−Dh) is set to zero.

In this way, after the positioning of the optical sensors 14R to 17R with respect to the front wheel 2R and the positioning of the optical sensors 14L to 17L with respect to the front wheel 2L, the controller 50 supplies the control signal Sc to the drive unit 34 to drive the motor 6 Operate. As a result, the roller 4 is rotated, and the front wheels 2R and 2L are rotated along with the rotation. In such a state, the optical sensor
When the valve 18R arranged on the front wheel 2R is detected by the 20R, the analog output Vx is sent from the optical sensor 20R to the A / D converter 26, and after being converted into digital data Dx by the A / D converter 26. Supplied to the controller 50. In this example, the position of the valve 18R is the reference position for the rotation of the front wheels 2R, and the next digital data Dx is supplied from the time when one digital data Dx is supplied to the controller 50. The digital data Da to Dd indicating the distances a to d detected by the optical sensors 14R to 17R in the period up to the point of time, that is, in the period of one rotation of the front wheel 2R is continuously transmitted from the A / D conversion units 22 to 25 to the controller 50. Is supplied in a regular manner.

On the other hand, in the front wheel 2L rotated together with the front wheel 2R, when the optical sensor 20L detects the valve 18L arranged in the front wheel 2L, the analog output Vy from the optical sensor 20L is detected.
Is sent to the A / D converter 32, converted into digital data Dy in the A / D converter 32, and then supplied to the controller 50. In this example, the position of the valve 18L is the front wheel 2L.
Is a reference position for rotation, and is a period from the time when one digital data Dy is supplied to the controller 50 to the time when the next digital data Dy is supplied, that is, one rotation period of the front wheel 2L. Optical sensor 14L to 17L
Digital data De indicating the distances e to h detected by
~ Dh are continuously supplied to the controller 50 from the A / D conversion units 28 to 31.

The controller 50 controls the digital data Da to Dd and De to
Based on Dh, the calculation based on the following formula, E = (Da + Db) / 2 ...... F = (Dc + Dd) / 2 …… G = (De + Df) / 2 …… H = (Dg + Dh) / 2 …… Go to the front wheels, as shown in Figure 2.
The average distance E between distances a and b and distances c and d for 2R
And an average distance F between the front wheels 2L and an average distance G between the distances e and f and an average distance H between the distances g and h are calculated.

Thus, in the controller 50, the distances E and F continuously calculated while the front wheel 2R makes one rotation, and the distances G and H continuously calculated while the front wheel 2L makes one rotation. Are respectively written as data with the rotation angles with the reference positions (positions of the valves 18R and 18L) of the front wheels 2R and 2L as zero degrees as addresses, and are sequentially written in the random access memory (RAM) 54. Here, the distance E out of the distances E to H written as data in the RAM 54
When F and F are equivalently represented by analog wavelengths with the rotation angle θ taken on the horizontal axis, they are as shown in FIGS. 3A and 3B, respectively. The data based on the distances E and F written in the RAM 54, which will be expressed as the changes in the distances E and F shown in FIGS. 3A and 3B, are obtained by comparing the axles of the front wheels 2R on the tire side of the front wheels 2R. It represents the amount of vibration peculiar to the reference line Or caused by the mounting error or the deformation of the tire. The same applies to the data based on the distances G and H, and represents the peculiar amount of deflection of the tire side surface of the front wheel 2L with respect to the reference line Ol due to the mounting error with respect to the axle of the front wheel 2L or the deformation of the tire. There is.

Then, the controller 50 calculates the toe-in amount T for the front wheels 2R and 2L based on the distances E and F for the front wheels 2R and the distances G and H for the front wheels 2L written in the RAM 54.

Here, the derivation process of the calculation formula used to calculate the toe-in amount T will be described with reference to the diameter of the front wheels 2R and 2L, the distance between the front wheels 2R and 2L, the distance between the tire side surface of the front wheel 2R and the reference line Or. , And the distance between the tire side surface of the front wheel 2L and the reference line Ol, etc., will be described below with reference to FIG.

From FIG. 2, T = B−A = B ₀ −A ₀ ...... A ₀ = 1− (E + G) / D ₀ × D …… B ₀ = 1− (F + H) / D ₀ × D ...... Is obtained.

Substituting the equation and the equation into the equation, T = [l− (E + G) / D ₀ × D] − [l− (F + H) / D ₀
× D] = [(E + G) − (F + H)] / D ₀ × D.

The formula thus derived is the calculation formula used for calculating the toe-in amount T.

Then, the controller 50, based on the data indicating the distance E, the data indicating the distance F, the data indicating the distance G, and the data indicating the distance H written in the RAM 54, the average values Ea, Fa, Ga and Ha of the respective distances. And the calculated average value Ea, F
Let a, Ga and Ha be E, F, G and H in the above equation, respectively.
The toe-in amount T for the front wheels 2R and 2L is calculated on the basis of the following equation: T = [(Ea + Ga) − (Fa + Ha)] / D ₀ × D.

When the toe-in amount T of the front wheels 2R and 2L is calculated in this way, the controller 50 supplies the control signal Sd to the display control unit 42 to display the calculated toe-in amount T on the display unit 40. Further, the controller 50 compares the calculated toe-in amount T with an appropriate toe-in amount To written in advance in the read-only memory (ROM) 52. As a result of comparison between the toe-in amount T calculated by the controller 50 and the appropriate toe-in amount To, if they are equal to each other, the toe-in amount measurement is ended without performing the toe-in adjustment on the front wheels 2R and 2L.

On the other hand, the toe-in amount T calculated by the controller 50
When the calculated toe-in amount T is different from the appropriate toe-in amount T ₀ as a result of the comparison between the toe-in amount To and the appropriate toe-in amount To,
Toe-in adjustment is performed on the front wheels 2R and 2L in order to eliminate the difference between the calculated toe-in amount T and the appropriate toe-in amount To. In addition, at the time of such toe-in adjustment, the front wheels
2R and 2L are kept stationary by being placed on the locked roller 4.

Then, after the toe-in adjustment is performed on the front wheels 2R and 2L, the controller 50 supplies the control signal Sc to the drive unit 34 to operate the stepping motor 6. As a result, the front wheels 2R and 2L are rotated by a predetermined rotation angle X ° with the reference position being zero, as shown in FIG.

In this way, with the front wheels 2R and 2L being rotated by X ° and standing still, the positions on the tire side surface of the front wheels 2R and 2L facing the optical sensors 14R to 17R and the optical sensors 14L to 17L are the front wheels. As the measurement site in 2R and 2L,
The distances a to d are detected by the optical sensors 14R to 17R, and A /
Digital data Da to Dd are obtained from the D conversion units 22 to 25 and supplied to the controller 50, and the optical sensors 14L to 1L
The distances e to h are detected by the 7L, and the A / D converters 28 to 31 are detected.
Digital data De to Dh are obtained from the controller 50
Is supplied to. The controller 50 responds to these new digital data Da to Dh, based on the above formula,
The new distances E to H are calculated as the distances E ', F', G'and H '.

At this time, the tire side surfaces of the front wheels 2R have the distances E and F before the toe-in adjustment is performed as shown in FIGS.
Has a characteristic shake characteristic such that it has a change equivalent to that shown by an analog waveform in, for example, at a measurement site rotated by a rotation angle X ° with the reference position being zero degree, Distance E is the average value
It has the displacement amount Ex from Ea, and the distance F is accompanied by the displacement amount Fx from the average value Fa. Also, the tire side of the front wheel 2L,
It has the same vibration characteristics as the front wheel 2R.
The distance G has a predetermined displacement amount Gx from the average value Ga and the distance H also has a predetermined displacement amount Hx from the average value Ha at the measurement site rotated by the rotation angle X ° with the reference position as zero degree.
Will be accompanied by.

Therefore, the controller 50 writes data indicating the distances E and F before the toe-in adjustment, which is written in the RAM 54, in order to eliminate the measurement error caused by the deflection characteristic of the tire side surface of each of the front wheels 2R and 2L. Among them, the one whose address is the rotation angle X ° is read out, and the shake amounts Ex and Fx are calculated from the difference between the distances E and F indicated by the read data and the average values Ea and Fa, and the toe-in adjustment is performed. Of the data indicating G and H before the execution, the data addressed to the rotation angle X ° is read, and the distances G and H and the average values Ga and Ha indicated by the read data are read.
The deviation amounts Ex.Fx, Gx and Hx are subtracted from the distances E ′, F ′, G ′ and H ′ calculated after the toe-in adjustment to calculate the shake amounts Gx and Hx from the difference between The corrected distances E to H after the adjustment are calculated as the distances E ″, F ″, G ″ and H ″.

In this way, after the toe-in adjustment, the front wheels 2R
And each of 2L are rotated once, and the distance E to H between them is rotated.
The distances E ″ to H ″ as the proper distances E to H can be obtained without performing the procedure of continuously calculating the average values Ea to Ha.

Then, the controller 50 determines the distances E ″ and F ″ for the front wheels 2R and the distances G ″ and H ″ for the front wheels 2L obtained after the toe-in adjustment as E, F,
The toe-in amounts T of the front wheels 2R and 2L are calculated based on the following equations obtained by substituting G and H: T = [(E ″ + G ″) − (F ″ + H ″)] / D ₀ × D.

In this way, the front wheels 2R and
When the 2L toe-in amount T is calculated, the controller 50
The proper toe-in amount To written in the ROM 52 is compared with the calculated toe-in amount T, and the display control unit 42 is supplied with the control signal Sd to display the calculated toe-in amount T on the display unit 40. Then, when the calculated toe-in amount T is different from the appropriate toe-in amount To, the toe-in adjustment is performed again on the front wheels 2R and 2L, and thereafter, the measurement of the toe-in amount is repeated as described above.

In the above example, the toe-in amount is measured for the front wheels 2R and 2L according to the wheel alignment measuring method according to the present invention, but the wheel alignment measuring method according to the present invention is, for example, for the front wheels. It can also be applied to the measurement of other factors in wheel alignment, such as the camber of the.

(Effects of the Invention) As is apparent from the above description, according to the wheel alignment measuring method of the present invention, the distance from the reference line to the measurement site on the tire side surface is detected after the alignment adjustment for the wheels is performed. , This distance is corrected based on the shake amount with respect to the reference line of the measurement site stored before the alignment adjustment is performed, and the alignment amount is calculated based on the distance from the corrected reference line to the measurement site on the tire side surface. Therefore, after the alignment adjustment, the distance from the reference line to any measurement site on the tire side surface is only detected, and the error due to the mounting error of the wheel on the axle or the deformation of the tire is corrected. In addition, a corrected alignment amount is calculated. Therefore, it is not necessary to rotate the wheel once for each measurement, and the time required for measuring the alignment with respect to the vehicle can be significantly shortened.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a toe-in measuring device used for carrying out an example of a wheel alignment measuring method according to the present invention, FIG. 2 is a diagram used for explaining a toe-in amount calculation, FIG. 3A and FIG. FIG. 4B is a diagram for explaining digital data written in the RAM used in the toe-in measuring apparatus shown in FIG. 1 according to an example of the wheel alignment measuring method according to the present invention, and FIG. 6 is a diagram which is used for explaining calculation of a toe-in amount in FIG. In the figure, 2R and 2L are front wheels, 4 is a roller, 6, 10R and 10L are motors, 14R, 15R, 16R, 17R, 20R, 14L, 15L, 16L, 17L and 20L are optical sensors, 18R and 18L are valves, 50 is the controller, 52
Is a read only memory and 54 is a random access memory.

Claims (1)

(57) [Claims] 1. A method of rotating a wheel, storing a shake characteristic of the tire side surface with respect to a reference line during one rotation of a specific portion of the tire side surface arranged on the wheel, and storing the shake characteristic, and then performing the operation. After alignment adjustment with respect to the wheel, the distance from the reference line to the measurement site on the tire side surface is detected, the relative position of the measurement site with respect to the specific site is detected, and the detected stored relative position is the shake. Corresponding to the characteristics, the shake amount of the measurement site with respect to the reference line is obtained, the detected distance is corrected based on the shake amount to obtain the corrected distance, and the corrected distance is calculated based on the corrected distance. A wheel alignment measuring method for calculating the amount of wheel alignment.