JP4511772B2 - Calculation rule for wheel alignment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus (toe gauge) for measuring the difference (toe) between the front and rear distances of left and right wheels in the wheel alignment of a suspension system (suspension) of an automobile. The present invention relates to a wheel alignment calculation rule used when using the.
[0002]
[Prior art]
A generally used device as a toe gauge is configured to measure an inclination angle of a wheel with respect to a traveling direction of a vehicle and display the angle as a toe angle. Therefore, when adjusting the wheel alignment, this toe angle is measured, but the maintenance manuals and specified values for automobile manufacturers in Japan are not the toe angle. Is defined by the toe distance (mm) expressed as a distance. Therefore, in the currently used toe gauge that displays an angle as a measured value, it is necessary to convert the toe angle into a toe distance in order to check the measured value of the measuring vehicle. .
[0003]
The relationship between toe angle and toe distance is
Since the toe distance (mm) = tan toe angle × tire outer diameter, if the tire outer diameter is known, the toe distance can be converted from the toe angle, and a calculation scale therefor is also known.
[0004]
However, in general, automobile tires are labeled with the tire width (mm), flatness (%), and wheel size (inch), for example, 195/55 R 15, but the outer diameter of the tire is not. It has not been. Therefore, in order to know the tire outer diameter, it is necessary to check the tire outer diameter by checking the tire catalog or measure the tire outer diameter, but the tire size varies depending on the vehicle, and there are many types. Therefore, such confirmation and measurement are troublesome, and toe measurement is often performed without grasping an accurate tire outer diameter.
[0005]
In addition, when the tire diameter is changed after changing the tire, the numerical value displayed on the vehicle speedometer will be different from the actual speed. I could not know the error easily.
[0006]
[Problems to be solved by the invention]
The problem to be solved by the present invention is that the tire outer diameter can be easily known based on the tire width, the flatness ratio, and the wheel size displayed on the tire as described above, and thereby the toe angle is made the toe distance. It is to provide a wheel alignment calculation rule that can be converted.
[0007]
Another problem to be solved by the present invention is to provide a wheel alignment calculation scale that allows the speedometer error to be easily known when the tire size is changed.
[0008]
[Means for Solving the Problems]
As described above, the tire width, flatness ratio, and wheel size are displayed on the tire, and the following formulas are established between them.
Tire flatness = tire cross section height ÷ tire width x 100,
Tire outer diameter = tire cross section height x 2 + wheel size.
Therefore, the tire outer diameter can be determined by obtaining the tire cross-section height from the tire width and the tire flattening ratio, doubling the tire cross-section height, and adding the wheel size. May be configured.
[0009]
That is, according to the present invention, a circular rotating plate is stacked on a substrate and connected to be rotatable at its center point, and a tire outer diameter scale is applied to the substrate in a circumferential direction with a divisional scale in a counterclockwise direction. The diameter / cross-section height scale, tire width scale, and toe distance scale are respectively applied to the logarithmic scale in a counterclockwise direction, and the outer diameter / cross-section height scale, tire width scale, and toe distance scale are provided on the rotating plate. A window that can be seen through is provided, a wheel size scale is provided in the circumferential direction in an anticlockwise direction, and a tire flatness scale corresponding to the tire width scale is provided in a logarithmic scale in the clockwise direction and the toe distance is provided. When the toe angle scale corresponding to the scale is applied in a counterclockwise direction with a logarithmic scale, and the tire flatness scale is combined with the tire width scale, the tire cross-section height calculated by the tire width and the tire flatness ratio is doubled. Is indicated on the outer diameter / section height scale above. Ca in so that the rotating plate - Hui, characterized in that a sol-ray - a slide rule for Le alignment is provided, the problems are solved.
[0010]
Further, according to the present invention, a percentage scale indicating a speed meter error calculated based on a difference in tire outer diameter is attached to the rotating plate on a logarithmic scale centered on the cursor line. The wheel alignment calculation rule is provided, and the above problems are solved.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of a calculation rule according to the present invention, and FIGS. 2 and 3 show a substrate (1) and a circular rotary plate (2) constituting the calculation rule shown in FIG. The substrate (1) and the rotating plate (2) are rotatably connected by inserting support shafts (5) such as shafts and pins through the center points (3) and (4).
[0012]
The substrate (1) has a tire outer diameter scale (6) from 0 to 1000 mm in the circumferential direction on the outer circumference, and is divided in a counter-clockwise direction on an equally divided scale. A diameter and cross-section height scale (7) is provided in a logarithmic scale in a counterclockwise direction. At this time, if the tire outer diameter scale (6) of 1000 mm is used as a reference and the outer diameter and cross section height scale (7) of 400 mm is aligned with this reference, the numerical value that is often used will be on the upper side in the figure. Because it is easy to use, it is not necessary to match. The outer diameter / cross-section height scale (7) is displayed in units of millimeters, but if an auxiliary inch scale (8) displayed in units of inches is provided on the outer side of the scale, it is displayed in units of inches. This is convenient for conversion.
[0013]
The substrate (1) is provided with a tire width scale (9) from 135 mm to 315 mm in a counterclockwise direction with a logarithmic scale of 10 mm intervals, and a toe angle is converted into a toe distance in the central portion. The toe distance scale (10) is provided in a logarithmic scale from 0.5 mm to 20 mm in a counterclockwise direction.
[0014]
The rotating plate (2) includes a window (11) through which the outer diameter / sectional height scale (7), the auxiliary inch scale (8), and the tire width scale (9) are provided on the substrate (1). A window (12) for seeing through the toe distance scale (10) is formed, and a wheel size scale (13) from zero to 36 inches is attached on the outer periphery in a counterclockwise direction with equally divided scales with inch intervals. It is. A reference mark (14) is provided at the zero position. In the figure, the rotating plate is composed of a transparent plastic plate or the like for the windows (11) and (12), but a connecting piece (not shown) is formed on a part of the window (11). If it does, it can comprise with the metal plate which punched each window.
[0015]
At the position facing the window (11) of the rotating plate, a tire flatness scale (15) is provided in a clockwise direction on a logarithmic scale from 20 to 82 so as to correspond to the tire width scale (9). When the tire width scale (15) is combined with the tire width scale (9), a numerical value that is twice the tire cross-section height calculated from the tire width and the tire flatness ratio based on the above-described formula is used. A cursor wire (16) is provided facing the window (11) at a position indicated on the diameter / cross-section height scale (7).
[0016]
In addition, at the position facing the window (12) of the rotating plate, the toe angle scale (17) corresponding to the toe distance scale (10) is counterclockwise on a logarithmic scale from 0 ° 05 'to 2 °. In the direction. As shown in the above formula, the toe distance can be obtained by tan toe angle × tire outer diameter. Therefore, the cursor line (16) indicates the tire outer diameter of the measuring vehicle and the outer diameter / section height scale. (7) When the rotating plate is rotated to the position indicated above, the toe angle scale (17) and the toe distance scale (10) are located at a position interval satisfying the above formula. 17) and toe distance scale (10) are provided. Note that the positional relationship of the tire outer diameter, the toe angle scale, and the toe distance scale is known in detail with a known calculation scale as described above, and therefore will not be described in detail.
[0017]
When the tire size of the vehicle is changed, the display of the speed meter is different from the display before the change. That is, the speed meter is based on the circumference of the standard tire, and the meter error due to the tire size change is caused by the difference between the circumference of the standard tire and the circumference of the tire after the change.
Tire circumference difference percentage (meter error percentage)
= 100-Change tire circumference ÷ Standard tire circumference x 100
It becomes. Further, since the tire circumference is the tire outer diameter × circumference ratio, the meter error percentage can be obtained by the following equation.
Meter error percentage = 100-changed tire outer diameter ÷ standard tire outer diameter × 100 Since the speed meter error based on the difference in tire outer diameter can be calculated as described above, The percent scale (18) indicating the speed meter error after the change is clockwise (with the cursor line (16) as the center and the outer diameter / section height scale (7) as a reference ( Plus) and counterclockwise (minus) are displayed on a logarithmic scale.
[0018]
In the figure, the reference mark (14) provided on the rotating plate (2) is provided on the extension line of the cursor line (16), but the reference mark (14) and the cursor line (16 ) May be offset in the circumferential direction.
[0019]
As an example of the case where the size attached to the tire is displayed as 195/55 R 15, the above-mentioned calculation scale will be used. The tire width is 195 mm and the flatness is 55%. The numerical value 195 of the tire width scale (9) is matched with the numerical value 55 of the tire flatness scale (15). Then, the numerical value indicated by the cursor wire (16) on the outer diameter / cross-section height scale (7) is a value twice the tire cross-section height.
[0020]
Check the same value as indicated on the outer diameter / cross-section height scale (7) on the tire outer diameter scale (6), and turn the plate (2) so that the reference mark (14) is at this position. Turn the wheel and read the tire outer diameter scale (6) indicated by the numerical value 15 on the wheel size scale (13) on the rotating plate (2). The numerical value is twice the tire cross-section height and the wheel size. Since it is the added numerical value, it becomes the tire outer diameter, and the tire outer diameter of the measurement vehicle can be known.
[0021]
In order to convert the toe angle measured by the toe gauge into the toe distance based on the tire outer diameter obtained as described above, the above-mentioned cursor wire (16) has an outer diameter and a sectional height. The rotary plate (2) is rotated to indicate the tire outer diameter on the scale (7), and the toe distance scale indicated by the measured toe angle on the toe angle scale (17). If (10) is read, the numerical value becomes the toe distance.
[0022]
Further, in order to know the error of the speed meter due to the tire outer diameter change, first, the tire outer diameter of the standard tire before the change that is currently mounted on the vehicle is obtained by the above-described procedure. Next, the tire outer diameter of the changed tire is obtained in the same manner as described above. Then, the rotating plate (2) is rotated so that the numerical value indicated by the cursor wire (16) on the outer diameter / cross section height scale (7) becomes the numerical value of the standard tire outer diameter before the change, When the percentage scale (18) indicated by the tire outer diameter value after the change is read, the numerical value becomes a numerical value indicating the speed meter error rate.
[0023]
【The invention's effect】
The present invention is configured as described above, and it is possible to know the tire outer diameter based on the tire width, the tire flatness ratio, and the wheel size displayed on the tire without using a catalog or actual measurement. After measuring the toe angle as a toe angle with a toe gauge, the toe distance (mm) can be easily changed by the tire outer diameter, and the tire outer diameter of the automobile can be easily confirmed. Therefore, it is possible to easily grasp the change in tire size by changing the tire size, the appropriateness of the tire flattening ratio by changing the tire width, etc. The error of speed meter due to can be easily confirmed by the percentage display, and can be used conveniently.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of the present invention.
FIG. 2 is a front view of a substrate.
FIG. 3 is a front view of a rotating plate.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Rotating plate 6 Tire outer diameter scale 7 Outer diameter and cross-sectional height scale 8 Auxiliary inch scale 9 Tire width scale
10-distance scale
13 Wheel size scale
14 Reference mark
15 Tire flatness scale
16 cursor wire
17 toe angle scale
18 percent scale

Claims (4)

A circular rotating plate is stacked on the substrate and connected to be rotatable at its center point, and a tire outer diameter scale is attached to the substrate in the circumferential direction in a counterclockwise direction, and an outer diameter and cross-section height scale, tire A width scale and toe distance scale are respectively provided on a logarithmic scale in a counterclockwise direction, and the rotary plate is provided with a window through which the outer diameter and cross section height scale, tire width scale, and toe distance scale can be seen through, A wheel-size scale is attached in the counterclockwise direction with an equally-divided scale and a tire flatness scale corresponding to the tire width scale is attached in a clockwise direction with a logarithmic scale and a toe-angle scale corresponding to the toe distance scale. Is applied in a counterclockwise direction on a logarithmic scale, and when the tire flatness scale is combined with the tire width scale, a value that is twice the tire cross-section height calculated from the tire width and the tire flatness ratio is used as the outer diameter / cross section. Place the cursor on the rotating plate to indicate on the height scale. Slide rule for Le alignment - Hui, characterized in that a line. The wheel alignment calculation rule according to claim 1, wherein a reference mark is provided at a zero position of the wheel size scale, and the reference mark is provided on an extension of the cursor line. The wheel alignment calculation scale according to claim 1 or 2, wherein the outer diameter / section height scale includes a scale displayed in millimeters and a scale displayed in inches. A percentage scale indicating a speed meter error calculated based on a difference in tire outer diameter is attached to the rotating plate on a logarithmic scale centered on the cursor line. 4. A ruler for wheel alignment according to any one of the above.

Images