JPH01107128A - Indoor test of snow tire - Google Patents

Abstract

PURPOSE:To perform the testing of a snow tire as tested on a simulated real road by a method, wherein a signal proportional to the real travel distance is output while a tire is run on an endless road simulator. CONSTITUTION:A tire support 4 is held by a linear bearing guide which is arranged in a direction parallel to the rotation axis of a drum 1, so that the whole body of the support 4 can be transported horizontally along the guide within the effective width of a simulated testing road 2 by a horizontal drive motor 8. A slip angle setting motor 9 provided on the support 4 adjusts the slip angle of a tire 5 by the rotation via a speed reducer 10. The tire 5 is connected via a power transmission device 11 to a dynamometer for tire 12, and the rotation axis of the drum 1 is connected to an encoder 13, which outputs signals proportional to the travel distance of the tire 5, and a dynamometer for drum 14. The slip angle of the tire 5 can be controlled by external signals or the like by driving the motor 9. On the other hand, a force generated on the tire is measured by a six-component force measuring device 6 with respect to the three-axial directions of the tire and a torque around the axis, separately.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an indoor testing method for tires for snowy and icy roads, and in particular, a test for the performance of tires on ice and a test for evaluating the degree of damage to paved roads caused by spiked tires, etc. It is related to the method of implementing the above.

Conventional technology] Tire on-ice performance tests have traditionally been conducted using outdoor fire experiments; however, (1) it is difficult to equalize the ice condition, temperature, etc.; Since it is not possible to conduct controlled experiments, there are problems such as the necessity to focus on full braking tests and pitching tests, and (3) the inability to ensure test repeatability. Also, when using a test vehicle for measuring the coefficient of friction, the drawbacks of (1) and (3) above are unavoidable.

On the other hand, it is possible to perform on-ice performance tests on drums or turntables, but because the length of the road surface used for driving is short,
As the vehicle repeatedly travels on the same road surface in short cycles, there are problems in that the temperature of the ice that forms the road surface rises by 1 or that the ice partially melts due to pressure melting. Furthermore, when testing damage to a paved road surface, the test may become impossible due to an increase in road surface temperature.

[Problems to be Solved by the Invention] An object of the present invention is to measure the road surface temperature by repeated running in short cycles using an indoor testing machine with a short road surface length for running, such as a drum-type tire testing machine. It is an object of the present invention to provide a method for conducting a tire on-ice performance test and a road surface damage evaluation test that can ensure repeatability while suppressing second rise.

[Means and effects for solving the problems] In order to achieve the above object, the indoor testing method for tires for snowy and icy roads of the present invention is as follows:
In a tire testing machine that has an endless road surface that can be repeatedly traveled on, it is possible to control the steering angle and lateral displacement of the tire.
By outputting a signal proportional to the distance traveled by the tire as the tire travels on the endless road surface, and synchronously controlling the steering angle and lateral displacement of the tire in proportion to the distance traveled, the tire does not generate side force. The vehicle is characterized by running in a slalom-like manner over the entire road surface.

More specifically, in the ice performance test of the tire and the road surface damage evaluation test based on the present invention, a tire testing machine that repeatedly uses the same road surface, such as a drum type or a turntable type, is used. This tire testing machine is
It is necessary that the steering angle (slip angle) and lateral displacement of the tire can be controlled from the outside, and it is also necessary that a signal proportional to the distance traveled on the road surface can be obtained.

Then, the steering angle and lateral displacement of the tires are synchronously controlled in proportion to the traveling distance, and the tires are driven in a slalom manner without generating side force. This makes it possible to reduce the frequency of driving at the same location, use the road surface uniformly, and prevent temperature rise.

In addition, it is possible to conduct an experiment in which a substantial slip angle is created by adding a constant steering angle to the steering angle in a state where the above-mentioned side force is not generated.

Such testing methods can be extremely effectively used to understand the mechanism of frictional force generation between icy surfaces and tires, and the mechanism of damage to dry road surfaces caused by spiked tires.

[Example] Figure 7II11 shows an example of an inside drum type tire testing machine suitable for use in tire testing by Kibatsu. This tire testing machine is equipped with a drum l rotatably supported on the edge of a horizontal axis with the inner surface serving as a test track 2, and a large number of asphalt segments are pasted on the inner surface of the drum l to create spikes. It is possible to simulate road surface damage caused by tires, and by protruding the collar 3 from the inner edge of the opening of the drum 1, it is possible to freeze water accumulated on the inner periphery and form an icy road surface on the inner periphery. It is something. Therefore, the main parts of this tire testing machine are installed in a prefabricated freezing chamber whose atmosphere can be arbitrarily set within the range of 0° C. to outside temperature.

The test tire 5 was supported on the tire support stand 4.

A method is adopted in which the drum is pressed horizontally against the inner surface of the drum by a pneumatic cylinder (not shown), and the ground load is adjusted by the air pressure applied to the L-shaped pneumatic cylinder. Suspension system 7 via total 6
The caster angle and the four can angles can be adjusted using support arms. In particular, the suspension system 7 is equipped with a double wishbone type suspension system and an air spring in order to bring the compliance of the suspension system closer to that of an actual vehicle, which is considered to be a problem in spiked tire tests.

The tire support stand 4 is supported by a linear bearing guide (not shown) disposed in a direction parallel to the rotational axis of the drum l, and the entire tire support stand 4 is moved along the guide by a transverse feed motor 8. Traverse feed is possible within the effective width of the trial track 2. Further, the slip angle setting motor 9 provided on the tire support base 4 adjusts the slip angle of the test tire 5 by its rotation via the reduction gear IO. Roughly, a tire dynamometer 12 is connected to the test tire 5 via an effect transmission mechanism 11,
On the other hand, an encoder 13 and a drum dynamometer 14 are connected to the rotating shaft of the drum 1, which output a signal proportional to the distance traveled by the tire.

In the L tire testing machine, the slip angle of the test tire 5 can be controlled by driving the slip angle setting motor 9 using an external signal or a programmable controller in the operation panel. In addition, the force generated in the tire is measured by a six-component force meter 6 using a piezoelectric element, which calculates the force in the three axes of the tire (ground load, traction force, side force) and the torque around these axes (self-aligning force). Torque, rolling resistance moment, overturning moment) are measured separately.

The drum can be controlled in three ways: constant speed, constant torque, and running resistance control using a DC dynamometer 14 installed outdoors. In addition, to control the power of the test tire shaft, the dynamometer 12 must be installed in a low-temperature room, and with a DC dynamometer, there is a high risk of problems with the brushes due to condensation.
Adopts a servo motor for constant torque and constant speed control.
It is made into Noh.

When using an indoor tire testing machine with the above configuration, the test road surface is endless, so when a spiked tire runs on the road surface in a straight line, the road surface corresponding to the track of the spikes is immediately damaged in a linear manner. This will prevent the spike from being effective. This inconvenience caused by tires repeatedly running over the same point on the test road surface occurs even with tires without spikes. FIG. 2 shows the temperature change on the test road surface when a slip angle is given so that a side force of 30 ON is generated with a wheel load of 2 kN without the tire being moved laterally. In this state, the surface temperature of the tire increases by 3°C to 4°C, and the temperature of the road surface increases accordingly, but this is because the tire runs repeatedly before the road surface releases the heat received from the tire. This is thought to occur in the following cases. The reason why the measured road surface temperature does not rise monotonically is because the indoor temperature is controlled by turning on and off the refrigerator.

In order to eliminate such inconveniences, a control device is attached to the above tire testing machine so that the test tire 5 is run in a slalom state without side force being generated, and the tire runs uniformly within the effective width of the test road surface. do.

In a tire testing machine equipped with this control device, the lateral feed and slip angle of the tire can be driven by external pulses at a rate of 0.01 m layer and 0.01 degree per pulse, respectively.

On the other hand, as the drum rotates, one rotation of the drum outputs 1024 pulses which are proportional to the travel distance of the drum.

Therefore, if the increase/decrease in the slip angle and the increase/decrease in the lateral displacement are given as external pulses according to the pulses output every time the vehicle travels a fixed distance, it is possible to travel on a travel trajectory with a fixed steering angle. Slalom is performed in a sinusoidal manner by selecting the period to be an integer multiple of the drum circumference + α, and the displacement Y of the tire at the traveling distance glx is as follows, where A is the amplitude of the slalom, L is the drum circumference, and ΔL. is a small value corresponding to α.

In order not to generate side force, the steering angle θ at each travel distance should be selected as follows.

Note that if x, y, and 0 are each given by pulse drive, only discrete values can be taken, so 0 and Y can also be determined as follows. In other words, the displacement Xn determined by equation (2)
Round the steering angle On to a realizable value, calculate the displacement Yn at Xn from this value and the travel distance,
Prepare a table on the computer for the increment/decrement Δθ and ΔYn. Next, for each pulse of travel distance caused by the rotation of the drum,
On, each control 4! A slalom is performed by adding to the l device.

The results of a slalom test conducted with the same wheel load and slip angle as in the straight-ahead test confirmed that there was no rise in road surface temperature or partial damage to the road surface even after one hour of continuous driving.

[Effects of the Invention] According to the method of the present invention detailed above, (1> rise in temperature of ice can be ignored).

(2) It is also possible to conduct tests on icy roads, which are similar to actual roads and have holes evenly formed, without any partial damage to the road surface caused by spiked tires or the like.

(3) Even in experiments on paved roads, due to abnormalities in road surface and tire temperatures, yI
This makes it possible to conduct experiments under conditions close to actual driving conditions.

[Brief explanation of the drawing]

Figure 1 is a general configuration diagram of a tire testing machine suitable for use in implementing the tire testing method of the present invention, and Figure 2 is a diagram showing the configuration of a tire testing machine when the slip angle is adjusted to generate side force on the tire. It is a graph showing temperature changes on the surface of a test road surface. 2. Test track, 5. Test tire, 8. φ transverse feed motor, 9. φ slip angle setting motor, 13. Encog. Designated Agent: Agency of Industrial Science and Technology, Mechanical Technology Research Institute, Director, Yoshige Mizukibe

Claims (1)

[Claims] 1. In a tire testing machine that has an endless road surface that repeatedly runs on and is capable of controlling the steering angle and lateral displacement of the tire, outputting a signal proportional to the traveling distance as the tire runs on the endless road surface, By synchronously controlling the tire steering angle and lateral displacement in proportion to the distance traveled,
An indoor testing method for tires for snowy and icy roads, which is characterized by running the tire in a slalom-like manner over the entire width of the road without generating side force.