KR20050120262A - Dynamic impact load addition and impact tester of tire tread - Google Patents

Abstract

The present invention is to measure the impact load applied from the uneven road surface in the room when the tire passes through the foreign matter such as stones, etc. existing on the road while driving on the road and the impact force applied to the tire tread at this time A tire tread portion dynamic impact load addition and impact amount measuring apparatus for evaluating the durability of the tread portion, comprising a measuring unit (7) for measuring the impact force due to the tire, the measuring unit 7 on the plate (4) A load cell 10 provided with a projection 9 provided in contact with the tire tread and a spiral coupling portion 9 in which the projection 9 is spirally coupled, and the load cell 10 passes through an amplifier 11 and a data processing unit. It is connected to (12).

Description

Dynamic impact load addition and impact tester for tire treads {Dynamic impact load addition and impact tester of tire tread}

The present invention is a load cell connected to a projection installed on the ground to the dynamic impact load generated by colliding with foreign matters such as stones existing on the road when the tire travels on the road impact load acting on the tire tread portion It relates to a tire tread portion dynamic impact load addition and impact amount measuring device for measuring.

Normally, tires pass through uneven parts such as lumps and puddles on the road as they travel on the road, and are subjected to impact loads due to collisions with ground obstacles.

Whether the irregularities are large or small, the tire is subjected to continuous dynamic impact loads while driving the vehicle, and at the same time, a very large tensile force is generated on the belt and the carcass cord of the impact part, thereby breaking the belt cord or the carcass cord of the tire tread part. Damage may occur, and such damage may cause a shock rupture of the tire, thereby causing an accident such as a vehicle overturning.

In addition, the dynamic impact force that continuously acts on the tread portion of the tire on an unpaved road or the like not only damages the tread portion of the tire, but also changes the spring stiffness of the tire and exerts a force on the tire bead portion, thereby making a difference between the tire bead portion and the wheel flange. Friction is induced to generate bead portion heat generation, and a shear force is generated between the carcass of the tire bead portion and the rubber of the lower end portion of the sidewall, thereby causing the bead portion to be damaged.

In designing the tire against the adverse effects of these dynamic impact forces on the tire,

The tire is designed so that the tread part is sufficiently rigid so that the tire tread part is not damaged by the dynamic impact load.

However, in order to design a tread section having sufficient rigidity to cope with such a dynamic shock, a so-called plunger test, which checks whether damage occurs by applying a steel rod of a certain size to the tread section only in a static state, It is implemented in accordance with the domestic KS standard and other tire durability related laws, and the test evaluation of the tire tread part for dynamic impact loads, which are generally three times larger than the static load, is not made.

In addition, there is a lumbar month to measure the force acting on the tire when the rotating tire passes the projection, which is installed by the load cell on the tire mounting shaft, after the impact force generated by the projection is absorbed by the tire, By measuring only the force transmitted to the axle, the impact force generated in the actual tire tread portion cannot be measured at all.

Therefore, the present invention was invented in view of the above-described conventional problems, and the present invention measures the impact load acting from the road surface when a tire travels on a road and passes foreign matters and puddles such as stones and the like that exist on the road. At this time, as a test device for evaluating the durability of the tread part by the impact force acting on the tire tread, after the simple evaluation of the damage occurrence of the tread part to the uneven part of the road in the room, develop a new tread rubber composition, or The purpose of the present invention is to provide a tire tread part dynamic impact load addition and impact amount measuring device to help develop a tread having excellent impact resistance against failure and to develop a tire without moving the bead part.

The present invention for achieving the above object is a load adding portion for applying a load to the tire mounted on the rotating shaft, a drive unit for linearly moving the load adding portion in a reciprocating manner on the bed, a position measuring device for detecting the rotation position of the tire, rotation It is made of a measuring unit that is subjected to a load and rotational movement while measuring the impact load by collision with the tire, the measuring unit is installed on the bed and the load cell having a projection and a spiral coupling portion that the projection is spirally coupled to the tread and The load cell is connected to the data processor via an amplifier.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The present invention measures the impact load applied from the uneven road surface when a tire travels on the road and passes through a foreign object such as a stone or the like on a road, and the durability of the tread part by the impact force acting on the tire tread. A tire tread portion dynamic impact load addition and impact amount measuring apparatus for evaluating the load, comprising: a load adding portion 3 for applying a load to the tire 2 mounted on the rotating shaft 1 as shown in FIGS. The driving part 5 for reciprocating linear movement of the load adding part 3 on the bed 4 is made up of a measuring part that receives a load while rotating and rotates and measures an impact load by collision with a tire. (8) is a load cell provided on the bed (4) with a projection (8) colliding with the tread (6) of the tire (2) and a spiral coupling portion (9) in which the projection (8) is helically coupled ( 10) and this The decell 10 is connected to the data processor 12 via an amplifier 11.

Here, the load adding portion 3 of the tire 2 is installed on the bed 4 that forms the running road surface of the tire 2 via the vertical frame 14, and the vertical frame 13 has an electric motor ( 14) and a screw jack 15 is installed, the rotary shaft (1) of the load adding portion (3) is connected to the screw jack 15, the tire (2) by the operation of the screw jack 15 is raised. , Position is adjusted downward.

On the other hand, the drive unit 5 is connected to the ball screw 16 provided on the longitudinal side of the bed 4 in the vertical frame 13 of the load adding unit 3, so that the drive by the electric motor 17 When the ball screw 16 is rotated, the load adding portion 3 is linearly reciprocated on the bed 4.

The data processing unit 12 of the measuring unit 7 includes a data collecting unit for collecting a signal applied by the load cell 10, a data storage unit, a data analyzing unit, an output unit, and the like, as is known. .

Next, the dynamic impact load measurement method for measuring the impact load applied to the tread 6 using the present invention will be described. First, when the tire 2 is driven, the tire 2 is rotated while the tire tread 6 is rotated. It collides with the projection 8 installed on the bed 4 and passes over the projection 8. The load detected by the voltage in the load cell 10 in which the projection 8 is helically fastened causes the amplifier 11 to be moved. It is stored in the data processing unit 12 through.

Here, the load cell 10 is to detect all the changes in the force applied to the load cell 10 from when the tire touches the projection to the complete departure.

On the other hand, in the load cell 10, in order to replace the foreign substances such as stones existing on the road, the projections 8 having a variety of shapes and sizes are fastened to each other in a spiral manner, the projections 9 are It has various shapes and surface roughness such as oval, circular, and polygonal according to the shape and size of typical stones on the road to be evaluated according to the test purpose, and is fastened with the load cell 10 according to the size of the protrusion to be tested. Of course, the depth can be adjusted.

Therefore, it is possible to measure under various conditions according to the air pressure, load, running speed and the size and shape of the projection of the dynamic impact load tire according to the present invention.

The results of the dynamic impact load measurement according to the present invention can be applied to the tire tread 6 design and the tire bead portion design, selecting the proper tire tread structure and strength for various projections, the structure of the tire bead portion without movement, and By selecting the strength, it is used to develop a tire having excellent durability without damage from impact from the road surface and a tire having excellent bead durability and steering stability since there is no bead movement.

In addition, after the test is completed, the tread part is subjected to visual observation to check for damage to the tread rubber, and to observe the inside of the tread such as belt and carcass cord reclamation using a non-destructive test device, thereby improving the durability of the tire tread part according to the impact load level. Evaluate.

Example

According to the tire pressure and load, the maximum value of the impact load from the tire contact with the protrusion to the complete release is compared with each other.

Exam conditions

Test Tire: 205 / 55R16 (100% Load: 525kgf. 100% Air Pressure: 2.0kgf / ㎠)

Tire running speed: 1,000m / min

Protrusion: Square section (50mm wide, 50mm long, 300mm long tire cross section length) Steel, surface roughness (▽)

Test 1: The test is carried out in the case of the same tread structure and rubber, the same air pressure, and different loads on the tire.

Additional load (kgf) Air pressure (kgf / ㎠) Travel speed (m / min) Protrusion (mm) (width X length X length) Test 1. 400 2.0 1,000 50 X 50 X 300 Test 2. 500 2.0 1,000 50 X 50 X 300 Trial 3. 600 2.0 1,000 50 X 50 X 300

Test Result: The greater the added load, the more impact load generated by collision with the protrusion

It is large and the ratio of impact load to added load becomes large.

Additional load (kgf) Impact load (maximum value) (kgf) Load ratio (%) (impact load / addition load) X 100 Test 1. 400 670 168 Test 2. 500 980 196 Trial 3. 600 1,350 225

Test 2: The test shall be carried out in the case of the same tread structure and rubber, the same load applied to the tire, and different air pressures.

Additional load (kgf) Air pressure (kgf / ㎠) Travel speed (m / min) Protuberance (width X length X length) Test 1. 400 1.6 1,000 50 X 50 X 300 Test 2. 400 1.8 1,000 50 X 50 X 300 Trial 3. 400 2.0 1,000 50 X 50 X 300 Trial 4. 400 2.2 1,000 50 X 50 X 300 Test 5. 400 2.4 1,000 50 X 50 X 300

Test Result: The greater the added air pressure, the greater the impact load caused by collision with the projection, and the greater the ratio of impact load to additional load.

In particular, when the air pressure of 3.2kgf / ㎠ showed that some of the belt cord is broken.

Air pressure (kgf / ㎠) Additional load (kgf) Impact load (kgf) Load ratio (%) (impact load / addition load) X 100 Test 1. 1.6 400 520 130 Test 2. 2.0 400 670 168 Trial 3. 2.4 400      940 235  Trial 4. 2.8 400 1,150 288 Test 5. 3.2 400     1,290 323

On the other hand, in the above embodiment of the present invention, but only for hemispherical projections, but various projections, such as oval, circular, polygonal and can be used for projections of the shape and dimensions of the side.

Tire tread rubber with various physical properties and treads with various stiffness can be tested, and the impact force according to the air pressure and running speed of the tire can be measured, and the damage and the tread of the tread part can be checked accordingly. Of course it can.

As described above, the tire tread unit dynamic impact load addition and impact amount measuring device according to the present invention can easily measure the impact force caused by the collision with the ground when the tire travels on a non-flat road surface, and various projections. By quantitatively measuring the impact force by using the data to help improve the durability of the tire has an effect that ultimately contributes to the improvement of tire quality.

1 is an overall plan view of a tire tread portion dynamic impact load addition and impact amount measuring apparatus according to the present invention,

Figure 2 is a side view of Figure 1, a side view showing an operating state,

3 is an enlarged cross-sectional view of the main portion of the present invention;

4 is a cross-sectional view of the projection used in the present invention.

Explanation of symbols on main parts of drawing

1: axis of rotation, 2: tire,

3: load part, 4: bed,

5: driving part, 6: tread,

7: measuring unit, 8: protrusion,

9: helical coupling portion, 10: load cell,

11: amplifier, 12: data processing unit,

13: vertical frame, 14: electric motor,

15: screw jack, 16: ball screw,

17: electric motor.

Claims (3)

A load adding portion 3 for applying a load to the tire 2 mounted on the rotating shaft 1, a driving portion 5 for reciprocating linear movement of the load adding portion 3 on the bed 4, and a load while rotating. It consists of a measuring unit (7) for measuring the impact force generated by colliding with the tire tread (6) that is given and reciprocated, the measuring unit (7) is installed on the bed (4) tread of the tire (2) A load cell 10 having a projection 8 that collides with (6) and a spiral coupling portion 9 in which the projection 8 is spirally coupled, and the load cell 10 is passed through an amplifier 11 to a data processing unit ( 12) Tire tread part dynamic impact load addition and impact amount measurement device connected to. The load adding portion 3 of the tire 2 is installed on the bed 4 forming the running road surface of the tire 2 via the vertical frame 13, and the vertical frame 13 is mounted. ), The electric motor 14 and the screw jack 15 is installed, the screw jack 15 is connected to the rotary shaft (1) of the load adding portion 3 by the operation of the screw jack 15 tire (2) is the tire tread portion dynamic impact load addition and impact amount measuring device, characterized in that the position is adjusted in the up and down directions. 2. The driving motor (5) according to claim 1, wherein the driving part (5) is connected to a ball screw (16) provided on the longitudinal side of the bed (4) with a vertical frame (13) of the load adding part (3). When the ball screw (16) is rotated by the tire tread portion dynamic impact load addition and impact amount measuring device, characterized in that made to linearly reciprocate the load adding portion (3) on the bed (4).