JPH06129954A - Drum testing device - Google Patents

Abstract

PURPOSE:To measure the force applied from a road surface to a tire accurately while covering a real speed and frequency range. CONSTITUTION:A drum main unit is supported by a drum bearing 18 and it is supported by a post 14 via a piezoelectric detection sensor 16. The circumferential speed of the drum main unit 20 can be set to 50km/h or more and a removable type road surface segment 24 with a surface which is obtained by casting an actual road in a mold is fixed on an outer peripheral. A tire press device 48 for pressing a tire 52 is placed at the side of the drum main unit 20. In the title device 10, the outer peripheral of the drum main unit 20 is covered with the removable type road surface segment 24 with the surface which is obtained by casting an actual road in a mold, thus obtaining a stationary and random road-surface input adapted to the actual road and accurately measuring the road-surface input of three crossing directions over a wide frequency range by the piezoelectric force detection sensor 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum tester for measuring the force received by a running tire from the road surface.

[0002]

2. Description of the Related Art In a conventional drum tester for running tests of tires, as a means for actually approximating the road surface condition, a surface with a safety walk, a surface with a wooden surface, or an artificial surface. Fix the protrusions,
There is a substitute for uneven road surface. As a means to measure the force applied to the tire from the road surface, a mechanism in which a part of the drum surface is supported by a force detector is used, and like the uniformity tester of the tire, it is caused by unevenness inside the tire. In order to measure the force, there is one in which load cells in three orthogonal directions are arranged on the drum shaft of a drum having a smooth surface.

[0003]

By the way, as a tire running test, it is desirable to measure the force applied to the tire from the road surface at an actual speed when running on various actual road surfaces. Further, since the force applied to the tire is constantly changing, it is desirable that the force can be accurately measured over a wide range of frequencies.

By the way, the force received by the running tire from the road surface is equal to the force transmitted to the tire shaft when the tire is subjected to only static deformation at a very low speed, and therefore A detector provided on the tire shaft can be used as a detector for the measurement. However, under normal driving conditions such as a speed of 20 km / h or more, the tire dynamically vibrates, and the force acting between the road surface and the tire tread surface is generally different from the force transmitted to the tire shaft. It is known.
What the present invention is concerned with is the force between the road surface and the tire, and therefore its measurement requires the provision of a detector on the road surface (drum) side.

However, a drum tester in which a part of the drum surface is supported by a force detector can cover the speed and frequency range, but only for a short time when the tire passes through the force detector on the drum surface. Since only data can be obtained, the road surface morphology is limited to pulse-like input such as a single projection, and is not suitable for steady random road surface input measurement.
In this case, the purpose can be achieved by enlarging the force detection unit on the drum surface over the entire drum surface, but in reality, the drum surface must be divided into fine segments, and a force detection sensor must be attached to each segment. It is uneconomical and impractical.

On the other hand, although some uniformity testing devices have a mechanism for detecting a force on the drum shaft, they are made on the assumption that the drum surface is smooth, and the speed is limited to a low speed. The strain gauge type load cell is used as a drum axial force detector, and the measurable frequency range is limited to a low frequency.

Further, since the surface shape of the drum is different from the actual surface shape of the road surface in any of the test devices, the force applied to the tire when the test device is run and the tire when the actual road surface is run. There is an error between the force applied to and.

In consideration of the above facts, an object of the present invention is to provide a drum test apparatus capable of accurately measuring a force applied to a tire from a road surface while covering an actual speed or frequency range.

[0009]

The invention according to claim 1 is
A drum for contacting an object to be tested with an outer periphery, and a detector for detecting a force acting in three directions orthogonal to a support portion of a shaft for rotating the drum,
In the drum testing apparatus including the above, the outer peripheral surface of the drum is formed as a real road surface over substantially the entire circumference, and the maximum value of the peripheral speed of the drum is set to 20 km / h or more.

The invention according to claim 2 is characterized in that, in the drum testing apparatus according to claim 1, the detector is a piezoelectric type detector.

[0011]

According to the drum test apparatus of the present invention, the tire, which is the object to be tested, is brought into contact with the outer periphery of the drum to rotate the drum, and the drum is detected by the detector provided on the support portion of the shaft. The forces in the three orthogonal directions acting on the tire, that is, the forces in the three orthogonal directions acting on the tire can be detected. In particular, the drum of the present invention has an outer circumference that is a real road surface over almost the entire circumference, and has a maximum peripheral speed of 20 km / h or more. It is possible to measure a stationary random road surface input over a long period of time.

According to the drum test apparatus of the second aspect of the invention, since the detector is a piezoelectric type detector, it is possible to accurately measure the force over a wide frequency range.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. Here, FIG. 1 is a plan view of a drum testing apparatus according to an embodiment of the present invention, FIG. 2 is a side view of the drum testing apparatus shown in FIG. 1, and FIG. 3 is a front view of the drum testing apparatus shown in FIG. .

As shown in FIG. 1, the drum testing apparatus 10 of this embodiment includes a base frame 12 placed on a foundation floor surface, and a pair of columns 14 are arranged on the base frame 12 at predetermined intervals. It is erected.

As shown in FIG. 4, drum bearings 18 are attached to the upper plane portions of the columns 14 via piezoelectric force detection sensors 16 as detectors attached at the four corners. The piezoelectric type force detection sensor 16 has a built-in piezoelectric element and can convert forces acting in three orthogonal directions (X, Y, Z axis directions, see FIGS. 1 to 4) into electric signals. The upper limit of the measurable frequency is 500 Hz or higher. Here, as the piezoelectric type force detection sensor 16, for example, a piezoelectric type three component force sensor manufactured by Kistler can be used. These piezoelectric force detection sensors 1
Reference numeral 6 is connected to a measurement value indicating amplifier (not shown) via a cable. Each piezoelectric force detection sensor 1
The mounting directions of 6 are all the same.

As shown in FIG. 1, a drum body 20 is arranged between the columns 14, and the drum body 20 is
It is pivotally supported by the drum bearing 18 via shafts 22 provided at both ends.

As shown in FIG. 3, on the outer periphery of the drum body 20, a real road divided into four in the circumferential direction (a rough asphalt pavement surface, a smooth asphalt pavement surface, a stone pavement, etc.) was molded. A removable road segment 24 having a surface is bolted.

As shown in FIG. 1, one drum bearing 18
The shaft 22 of the drum body 20 is projected to the side of the
A shaft 28 is coaxially arranged on the distal end side via a flexible coupling 26. This axis 28 is connected to a second base frame 30 arranged laterally of the base frame 12.
Bearings 34 mounted on the upper part of the columns 32 standing upright
Is supported by. A brake disc 38 of a brake device 36 is fixed to the shaft 28 between a bearing 34 and a flexible coupling 26. The brake disc 38 is a friction material of a brake disc caliper attached to an upper portion of a column 32. A rotation (not shown) is pressed to stop the rotation.

A pulley 40 is fixed to the tip of the shaft 28, which protrudes to the side opposite to the brake disc 38 side of the bearing 34. Below the pulley 40, a pulley 44 is arranged via a power transmission belt 42,
The pulley 44 is rotated by an electric motor 46.

The rotation speed of the electric motor 46 is variable, and the rotation speed of the drum body 20 can be at least 20 km / h or more. The drum body 20 of this embodiment has a peripheral speed of 50 km / h or more.

As shown in FIGS. 2 and 3, the drum body 2
A tire pressing device 48 is arranged laterally in a direction orthogonal to the axial direction of 0, and a tire 52 as a test object mounted on a wheel 50 of the test tire pressing device 48 is
The cylinder device 54 of the tire pressing device 48 can press the drum body 20.

Next, a tire running test method using the drum test apparatus 10 of this embodiment will be described.

First, a predetermined removable road surface segment 24 is bolted to the outer periphery of the drum body 20. Then, the drum body 20 is rotated at a predetermined speed by the electric motor 46, and the tire 52 of the test tire pressing device 48 is pressed by the cylinder device 54 against the removable road surface segment 24 of the drum main body 20 with a predetermined load to generate a piezoelectric force. The detection sensor 16 measures the force acting in each direction.

In the drum testing apparatus 10 of the present embodiment, the outer periphery of the drum body 20 is entirely covered with the removable road surface segment 24 having a surface which is formed by molding the actual road, and the peripheral speed of the drum body 20 is 50 km / h. As described above, it is possible to obtain a steady random road surface input that conforms to the actual road, and it is possible to accurately measure road surface inputs in three orthogonal directions over a wide range of frequencies with the piezoelectric force detection sensor 16. it can.

5 (A), (B), and (C),
Three types of tires (tire size 195 / 65R14, internal pressure 2.0, respectively) measured by the drum test apparatus of this example
An example is shown in which the actual forces in three orthogonal directions (kg / cm ² , load 350 kg) (velocity at the time of measurement is 50 km / h at drum peripheral velocity) are measured.

Here, the graph of FIG. 5A shows the vertical force of the tire (the vertical direction when the vehicle is mounted, not the vertical direction in the drum testing apparatus), and the graph of FIG. The tire front-rear force (front-rear direction in the vehicle mounted state) is shown, and the graph in FIG. 5C shows the tire left-right (axial direction in the vehicle mounted state) force. The vertical axis of the graph represents the force value, which is logarithmic with 0 kg as 1 kgf. The horizontal axis of the graph is frequency.

[0027]

Since the drum testing apparatus of the present invention is constructed as described above, it has an excellent effect that the force applied to the tire from the road surface can be accurately measured while covering the actual speed and frequency range.

[Brief description of drawings]

FIG. 1 is a plan view of a drum testing device according to an embodiment of the present invention.

2 is a side view of the drum testing device shown in FIG. 1. FIG.

FIG. 3 is a front view of the drum test apparatus shown in FIG.

FIG. 4 is a perspective view of an upper portion of a support column showing an arrangement state of piezoelectric force detection sensors.

5A is a graph showing the vertical force of the tire measured by the drum test apparatus of the present embodiment, FIG. 5B is a graph showing the longitudinal force of the tire, and FIG. It is a graph which shows power.

[Explanation of symbols]

 10 Drum Test Device 16 Piezoelectric Force Detection Sensor (Detector) 20 Drum Main Body 24 Detachable Road Surface Segment 52 Tire (Test Object)

Claims (2)

[Claims] 1. A drum testing apparatus comprising: a drum for contacting an object to be tested with an outer periphery; and a detector for detecting a force acting in three directions orthogonal to a supporting portion of a shaft for rotating the drum, wherein Almost the entire circumference is made a real road surface,
A drum test apparatus, wherein the maximum peripheral speed of the drum is set to 20 km / h or more. 2. The drum test apparatus according to claim 1, wherein the detector is a piezoelectric type detector.