JPS58148908A - Device for measuring static load radius of automobile tire - Google Patents

Abstract

PURPOSE:To measure the static load radius of a tire statically and precisely by fixing one end of a scale which contacts with the outer circumference of the tire at specific height from a horizontal surface and moving the other end along the outer circumference of the tire in measuring each external diameter at many points. CONSTITUTION:On a horizontal plate 1, the tire 2 is placed and at one upper end of a parallel table 3, a small roller-like contactor 6 is set in contact with the outer circumference of the tire. Then, the scale 5 for measuring the external diameter of the circumference is placed in contact with the outer circumference of the tire while the center of the roller is regarded as the fulcrum. The measurement scale 5 rotates around the center of the roller as the fulcrum along about a half the circumference. At the other end of this scale 5, another roller- like contactor 7 is provided and moves along the outer circumference of the tire all the time to measure outer diameters of the circumference at respective points. Thus, the static load radius of the tire is measured statically and precisely.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for measuring the static load radius of a tire (hereinafter simply referred to as a tire) fitted to the rim of an automobile wheel.

Conventionally, to statically measure the static load radius of a tire, the height from the tangential plane to the shaft center was measured with a constant static load applied to the shaft center. In actual measurement, a relatively large measurement error may occur in the process of determining the axis center and matching the scale to that point. The present invention does not directly determine the axis center, but
Simply from measuring the outside diameter on the tire's circumference.

It measures the static load radius.

The measurement principle will be explained with reference to FIG.

A tire 2 is placed on the top of a horizontal plate 1. The vertical distance r from the tire axis center 0 to the horizontal plate l is the static load radius.

Now, a parallel stand 3 with a constant height of 4 h is placed on a horizontal plate, and the point of contact with the outer circumference of the tire is set as a. Now, using this point a as a reference point, measure the length of the outer diameter of the tire's circumference -1-. (Hereinafter, this will be referred to as the circumferential outer diameter.) First, the circumferential outer diameter l in the horizontal case. , the angle at that time is Oo, but as the angle θl gradually increases.

The set of circumferential outer diameters becomes large and reaches its maximum when passing through the axis center 0, and after that even if θ1 increases υ■, l di gradually decreases.
ν. In other words, the position where 11 is at its maximum is equal to the diameter I) of this tire throughout its axial center.

Now calculate l+ and θ at each measurement point using the general least squares method.

By performing data processing, the maximum value of +4 and the angle θL at that time can be determined. From the figure 1. /2-rO2
1・-]), and the height h from the ilZ row stand 1- to the axis center 0 is h = '/2 m sin θ, -=r
. sin θL, and the static load radius r is.

r-koh+r. sinθ, ...song ...song (
1). Since this is the height of the JhVip row stand.

, easily measurable. In this way, 2 circumference outer diameter t
'1 and its angle θ1 at multiple points, the static load radius can be measured.

FIG. 3 is a schematic diagram shown in FIGS. 2 and 3 of a static load radius measuring device actually installed in an automobile.

A tire 2 is placed on 1- of the horizontal plate 1. A small roller-shaped contactor 6 is placed on one of the upper ends of the running platform 3 in contact with the outer circumference of the tire. Using the center of this roller as a fulcrum, a measuring scale 5 having an outer diameter of two circumferences rotates along approximately half the circumference of the tire. On the other side of this scale 5 is a contact 7 which is also in the form of a roller. It moves along the outer circumference of the tire from time to time and measures one circumferential outer diameter at each point.

At the same time, an angle scale 8 is vertically arranged on the 1P row stand 3. The length from the center of roller 6 to the graduation surface t of this angle scale is d, and the length between each measurement is taken as d. Let dl be the height of the intersection of the measurement scale 5 and the angle scale 8.

fan ' == ' ・Song, song, song...
The angle θ1 corresponding to the outer diameter 11 of the 9th circumference is determined from the curve (21). Here, when θ1-0, the measurement scale 5 is positioned horizontally.

In this way, if the length 11 at each arbitrary point and the corresponding angle θ1 are found.

Apply this to the quadratic equation and find the coefficients of each term.

From this, the maximum value of the glue and the angle θ at that time are determined.

FIG. 4 is a diagram showing these relationships. Now, let the diameters of the rollers 6.7 of both contacts be Δr, and the radius of the tire 2 be r. Then, h-(LO”)/2*5
+nθL, and the static load radius ``is determined as r=blood, Δh, U, 2, sin θ, (3).

The object of the present invention is to statically, easily, and precisely measure the static load radius of a tire while it is attached to an automobile as described in H below.

This is a device for measuring the static load radius of automobile tires.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram showing the measurement principle of the present invention. FIGS. 2 and 3 are explanatory diagrams of embodiments of the present invention, and FIG. 4 is an explanatory diagram showing the correction relationship of dimensions in actual measurements. １・・・・・・・・・・・・・・・Horizontal plate 2 ・・・
・・・・・・・・・・・・ Tire 3・
・・・・・・・・・・・・Parallel stand

Claims (1)

[Claims] A tire attached to a car while it is running. The tire is held stationary on a horizontal plate 1-, and one end that contacts the outer circumference of the tire is fixed at a constant height from the surface of the water, and the other end is moved along the outer circumference of the tire while measuring each outer diameter. A device that measures the length at multiple points, simultaneously determines each angle, calculates the liquid length of the outer diameter and the angle at that time, and measures the static load radius of the tire from this.