JPH049453B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for detecting imbalance in the running state of wheels of an automobile or the like. (Prior Art) Conventionally, the following method has been known as a so-called "on-the-car" detection method for detecting unbalance of a wheel when it is attached to a vehicle body such as an automobile. For example, in the system described in Japanese Patent Publication No. 46-4402, the lower arm is jacked up via a vibration detector, and the vibration detector is also brought into contact with the back surface of the brake support plate, so that the wheel can be adjusted in the vertical direction and the king pin. It detects vibrations around the axis of the What is described in Japanese Patent Application Laid-Open No. 59-217129 is
After detecting the weight imbalance of the wheels, the uniformity imbalance is detected. (Problems to be Solved by the Invention) According to the former of the above-mentioned conventional techniques, it is necessary to move the vehicle body up and down each time measurement is performed, and
Since the various detectors must be brought into contact with the lower arm and the brake support plate at the same positions, there is an inconvenience that work time increases and it is not possible to detect tire uniformity imbalance. According to the latter of the conventional techniques, it is necessary to move the vehicle body up and down each time a measurement is made, and when a rotating roller is brought into contact with the wheel and rotated to detect and correct a weight imbalance, Since the correction includes the influence of the uniformity imbalance, there were inconveniences such as the need to confirm the presence or absence of weight imbalance again after the next correction of the uniformity. SUMMARY OF THE INVENTION An object of the present invention is to provide a wheel unbalance detection method that is free from the conventional disadvantages. (Means for Solving the Problems) The present invention is a method for detecting unbalance of a wheel attached to a vehicle body such as an automobile, in which the wheel is placed on a rotating drum, and the wheel is detected by the unbalanced weight of the wheel. The wheel rotates at a low speed that does not cause vibrations, detects the unbalanced uniformity from the vibration of the wheel at that time, and after correcting the unbalanced uniformity, rotates at a higher speed than the above speed, and detects the unbalance from the vibration of the wheel at that time. It is characterized by detecting weight imbalance. (Example) Hereinafter, an example of the present invention will be described with reference to the drawings. In the drawing, 1 is a wheel attached to a vehicle body 2 of an automobile, etc., 3 is a rotating drum rotated by a driving motor or by the driving force of an automobile, etc. via the wheel 1, 4 is a non-contact displacement meter, and 5 is a rotating drum. 6 shows a small articulated robot for installing the non-contact displacement meter 4 at a predetermined position, and 6 shows a position detector consisting of a light emitting element and a light receiving element and detecting the unbalanced position of the wheel 1. The non-contact displacement meter 4 is, for example, a commercially available non-contact optical displacement meter, and as shown in FIG. It consists of a condensing lens 8 for forming a point, a lens 9 for condensing scattered light generated on the surface of the object, and a photo-sensing element 10 placed at the focal point position and responding to the position of the bright spot. The change in the position of the surface of the non-measurable object Bd shown in A and FIG. 3B is extracted as a change in the bright spot position on the photo-sensing element 10, and the displacement of the non-measurable object is measured. Next, the unbalance detection method of the present invention will be explained. The unbalance of the wheel 1 includes (a) uniform unbalance due to uneven spring constant in the circumferential direction or width direction of the tire, (b) unbalance due to variation in the outer diameter of the tire, and (c) drive system. (d) static unbalance, which is an unbalanced load in the circumferential direction of the wheel 1 including braking system unbalance; and (d) dynamic unbalance, which is an unbalanced load in the width direction of the wheel 1. The uniform imbalance is the variation in force in the tire's radial direction (radial force variation, RFV).
and force variation in the width direction of the tire (lateral force variation, LFV). When there is an imbalance as described in (a), (b), (c), or (d) above, the rotating wheel 1 will experience any of the following vibrations: vertical vibration, longitudinal vibration, and turning angle direction vibration, as shown in Table 1. 1
vibrate one or some combination of them.

[Table] According to the proposed method, vibrations due to unbalances (c) and (d) among the unbalances (a), (b), (c), and (d) above are Focusing on the fact that this does not occur at low speeds, first rotate the wheel 1 at the low speed, detect the uniformity imbalance from the vibration, and after correcting the unbalance, rotate at the high speed at the above speed, and then The weight imbalance is detected from the vibration of the wheel 1. To explain this in more detail below, the wheel 1 attached to the vehicle body 2 is placed on the rotating drum 3 while other wheels (not shown) are clamped by a tire clamp device, and the wheel 1 is moved at the low speed, e.g. per hour
The wheel 1 rotates at a speed of about 10 km/h or less, and the vibration of the wheel 1 at that time is detected. Regarding the vertical vibration of the wheel 1, the non-contact displacement meter 4 is placed opposite the lower surface of the lower arm 11 by the robot 5 (at the position shown in FIGS. 1 and 2), so that the infrared rays are perpendicularly incident on the lower surface. Detection is performed by measuring the amount of displacement of the lower arm 11 in the vertical direction. Regarding vibrations in the direction of the turning angle of the wheel 1, the non-contact displacement meter 4 is placed opposite the surface of the splash guard 12 formed by the robot 5 (position shown in FIGS. 1 and 2), and the infrared rays are perpendicular to the surface. It is detected by measuring the amount of displacement of the splash guard 12 in the direction of the cutting angle. The vertical vibration of the wheel 1 that occurs at this time is due to the RFV of the uniform unbalance and fluctuations in the outer diameter of the tire.The relationship between the amount of removal corresponding to the amount of unbalance due to RFV and the amount of displacement in the vertical direction is determined in advance. It is stored in a chart or in a memory, and the deletion amount corresponding to the measured displacement amount is determined from the contents of the chart or memory. The unbalanced position of the wheel 1 is determined as follows. A reflective tape is attached to an arbitrary position on the wheel 1, and a position detector 6 is placed at a position where the tape passes when the wheel 1 rotates. As a result, the light reflected from the emitting element enters the light receiving element of the position detector 6 each time the tape passes when the wheel 1 rotates.
A pulse signal is output from the element. Therefore, this pulse signal is compared with the positional displacement signal output from the displacement meter 4, and the unbalanced position of the wheel 1 is determined from the phase difference between the two. Next, if it cannot be corrected by first changing the mounting position of the tire on the rim, then the circumferential surface of the tire at the unbalanced position is removed by the amount of unbalance using a grindstone or the like to correct it. Also, the vibration in the turning angle direction of the wheel 1 that occurs at this time is due to the LFV of the uniform unbalance, and the amount of removal corresponding to the unbalance amount is calculated from the displacement amount in the turning angle direction measured by the same method as above. , and find the unbalanced position. Next, the unbalanced tire is corrected by removing the unbalanced amount in the width direction using a grindstone or the like. At the end of the modification, the speed is higher than before, for example 80
The wheel 1 is rotated at a speed of ~120 Km/h. The vertical vibration and longitudinal vibration of the wheel 1 that occur at this time are due to static unbalance, and the weight corresponding to the unbalance is determined from the measured vertical and longitudinal displacement using the same means as above. Find the unbalanced position. Further, the vibration in the turning angle direction of the wheel 1 that occurs at this time is due to dynamic unbalance, and from the displacement amount in the turning angle direction measured by the same means as above, a weight corresponding to the unbalance amount is calculated, and Find the unbalanced position. Next, attach a weight corresponding to this unbalance to each unbalanced position of the wheel 1,
Correct the imbalance. (Effects of the Invention) According to the present invention, since the uniformity is corrected in advance, the weight balance only needs to be checked once, and since it is carried out in the actual vehicle condition, drivability can be improved more than when only a single tire is used. It has the effect of being measurable.

[Brief explanation of drawings]

Figures 1 and 2 are a front view and a view taken along the line A-A in Figure 1, and Figures A and B are non-contact type when the object to be measured is displaced. It is an explanatory diagram of an example of operation of a displacement meter. 1...Wheel, 2...Car body, 3...Rotating drum,
4...Non-contact displacement meter, 5...Robot, 6...
Position detector, 11...Splash guard, 12
...Lower arm.

Claims (1)

[Claims] 1. In a method for detecting unbalance of wheels attached to the body of an automobile, etc., the wheels are placed on a rotating drum, and the wheels are rotated at a low speed that does not cause vibrations due to the unbalanced weight of the wheels. A vehicle, etc., characterized in that a uniform unbalance is detected from the vibration of the vehicle, and after the uniform unbalance is corrected, the vehicle rotates at a higher speed than the aforementioned speed, and a weight unbalance is detected from the vibration of the wheels at that time. A method for detecting unbalance of wheels.