JPH0545154A - Tire-radius measuring system of dump track - Google Patents

Abstract

PURPOSE:To enable a tire radius at the time of loading scanning to be measured accurately by measuring a pressure of a rearwheel suspension cylinder. CONSTITUTION:When a vehicle stops, a tire radius calculator 20 receives a vehicle stop signal from a vehicle stop detection means 21, reads a rear-wheel suspension cylinder pressure Pa and a vehicle inclination angle from an inclination meter 6 for each specified time interval, and then stores it into a memory 22. When the vehicle is driving, namely when no vehicle stop signal can be detected. the calculator 20 calculates a tire radius based on a tire free radius within the memory 22, a tire load-radius characteristic, a rearwheel suspension cylinder rod outer diameter, a spring lower load, the rear-wheel suspension cylinder pressure Pa, a vehicle body inclination angle, and an inclination compensation coefficient. The calculated tire radius is output to a system such as an automatic driving system of a dump truck.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for measuring the tire radius of a dump truck during operation.

[0002]

2. Description of the Related Art The mileage of a dump truck is calculated based on the transmission output speed, tire radius, etc., but since the tire radius changes depending on the presence / absence of options, the empty vehicle weight due to the amount of fuel / grease / water, and the load capacity, An error will occur between the calculated traveling distance and the actual traveling distance. As described above, if an error occurs between the calculated travel distance and the actual travel distance, an error occurs between the travel distance set and the actual travel distance when the dump truck is automatically traveled, and the control cannot be performed accurately. For this reason, conventionally, the tire radius when the vehicle is loaded is calculated in advance by the standard empty vehicle weight and the rated load weight based on the spring constant of the tire, and the two tire radii are stored in the controller of the automatic running control system and the empty vehicle running is performed. In some cases, one of the two values is called during loading and traveling to calculate the traveling distance.

[0003]

However, the weight of the empty vehicle differs depending on the individual vehicle or at that time due to the presence or absence of options and changes in the amount of fuel and oil / fat, and the load weight varies depending on the type of load and the load condition. Therefore, it is not possible to accurately measure the tire radius during loading and running.

Therefore, an object of the present invention is to provide a tire radius measuring system for a dump truck, which can solve the above-mentioned problems.

[0005]

A tire radius measuring system for a dump truck comprising a means for detecting the pressure of a rear suspension cylinder supporting a rear wheel when the vehicle is stopped, and a means for calculating a tire radius in consideration of the detected pressure. .

[0006]

[Operation] Since the axle weight acting on the rear wheels can be known from the pressure of the rear suspension cylinder, the tire radius at each time can be accurately measured.

[0007]

[Example] As shown in FIG. 1, front wheels 2 are supported on the front left and right sides of a vehicle body 1 through front wheel suspension cylinders 3, and rear wheels 4 are rear wheel suspensions 5 on the rear left and right sides of the vehicle body 1.
And a vessel is movably attached to the vehicle body 1 to form a dump truck, and an inclinometer 6 is attached to the vehicle body 1. As shown in FIG. 2, the rear wheel suspension cylinder 5 has a cylinder tube 10 into which a piston 12 having a piston rod 11 is inserted to form an extension chamber 13 and a reduction chamber 14, and the extension chamber 13 is provided with oil and nitrogen gas. , While enclosing oil in the reduction chamber 14,
The structure communicates with the pores 15 and has a structure in which the magnitude of the external force F can be known by detecting the pressure in the extension chamber 13, and a pressure sensor 16 for measuring the pressure in the extension chamber 13 is provided. As shown in FIG. 3, the tire radius calculator 20 such as a central processing circuit receives the rear suspension cylinder pressure Pa from the pressure sensor 16, the vehicle stop signal from the vehicle stop detector 21, and the inclinometer 6 from the inclinometer 6. The vehicle body inclination angle is input, and the memory 22 stores the tire free radius, tire load-radius characteristics, rear wheel suspension cylinder rod outer diameter, unsprung load, and rear wheel suspension cylinder pressure P.
a, a vehicle body inclination angle, and an inclination correction coefficient are stored.

Next, the measurement of the tire radius of the rear wheel 4 will be described. When the vehicle is stopped, a vehicle stop signal is input to the tire radius calculator 20 from the vehicle stop detector 21, for example, a wheel rotation detector, and the tire radius calculator 20 reads the rear wheel suspension cylinder pressure Pa at predetermined time intervals. The latest rear suspension cylinder pressure Pa is sent to the memory 22 and stored in the memory 22. At this time, old data may be deleted. At the same time, the vehicle body inclination angle from the inclinometer 6 is stored in the memory 22. When the vehicle stop signal is no longer input from the vehicle stop detection means 21, it is determined that the vehicle is traveling, the pressure reading of the pressure sensor 16 of the tire radius calculator 20 is stopped, and the tire free radius in the memory 22 is determined.
The tire radius is calculated based on the load-radius characteristic of the tire, the rear wheel suspension cylinder rod outer diameter, the unsprung load, the rear suspension cylinder pressure Pa, the vehicle body inclination angle, and the inclination correction coefficient. Send to other systems such as automated driving systems. In the above system, the vehicle body inclination angle from the inclinometer 6 is because the external force acting on the rear suspension cylinder 5 changes depending on the vehicle body inclination angle when the vehicle is stopped, which causes an error from the case of a flat ground. The tire radius is calculated by selecting the inclination correction coefficient according to the angle.

[0009]

EFFECT OF THE INVENTION Due to the pressure of the rear wheel suspension cylinder 5, the rear wheel 4 in the condition of the vehicle and the loaded weight in the vessel is
Since the weight acting on the tire radius can be known, if the pressure of the rear suspension cylinder 5 is added to the tire radius calculation, the tire radius at that time can be correctly measured.

[Brief description of drawings]

FIG. 1 is a perspective view of a vehicle support portion of a dump truck.

FIG. 2 is a sectional view of a rear wheel suspension cylinder 5.

FIG. 3 is a tire radius calculation circuit diagram.

FIG. 4 is an operation flowchart of tire radius calculation.

[Explanation of symbols]

1 body, 2 front wheels, 3 front wheel suspension cylinders, 4 rear wheels, 5 rear wheel suspension cylinders, 6
Inclinometer, 16 pressure sensor, 20 tire radius calculator,
22 memory.

Claims (1)

[Claims] 1. A dump truck in which a rear wheel 4 is supported on a vehicle body 1 by a rear suspension cylinder 5, and a vessel is provided on the vehicle body 1 so that the vessel can be raised and lowered. A means for detecting the pressure of the rear suspension cylinder 5 when the vehicle is stopped. A tire radius measuring system for a dump truck comprising means for calculating the tire radius of the rear wheel 4 in consideration of the detected pressure.