JP2006194813A - Pneumatic tire-testing method and tester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire-testing method and a tester for efficiently reproducing tearing similar to the tearing of a tread coming into existence in the market and evaluating tear resistance of a tire. <P>SOLUTION: A test tire 1 combined with a rim is given a prescribed inner pressure. Prescribed load is loaded thereon to bring a tread into contact with a planar surface of a mounting table. A rod-like projection 2 fixed on the surface of the mounting table is brought to a state where it is covered with a circumferential groove 1b of the test tire 1 extending over a grounding area with the mounting table for the test tire 1 and a non-grounding area. The mounting table is turned centering around a rotation axis P substantially coinciding with a direction normal to the surface thereof to give an external force to a rib 1a by means of the rod-like projection 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a test method and a test apparatus for a pneumatic tire. More specifically, the present invention relates to a pneumatic tire that can efficiently and accurately reproduce the tread tier generated in the market and evaluate the tire tear resistance. The present invention relates to a test method and a test apparatus.

  Conventionally, tires for heavy loads used for trucks, trailers, etc., especially pneumatic tires attached to steer shafts, have had so-called tiers where the tread ribs and blocks have been torn off. It wasn't.

  Therefore, the only way to evaluate the tear resistance of tires is to use an evaluation method that investigates the rate of tire tears in actual vehicles. In this method, it is necessary to evaluate a large number of tires in order to improve the evaluation accuracy. It was time consuming and costly and was not efficient.

  In addition, this method does not clarify the cause of tiers, so comparing tires with different specifications can only be evaluated by the presence or absence of tiers, and the level of tiers that occur cannot be compared. .

  As an evaluation device that reproduces cracks and chips generated in the thin ribs provided on the shoulder edge of a pneumatic tire, the test tire is run on the base in a circular path, and the protrusions are placed on the circular path. And what makes a test tire get on is proposed (refer patent document 1).

However, this device could not reproduce the tier generated in the market only by reproducing cracks and the like due to repeated curbstones and overpasses in the market.
Japanese Utility Model Publication No. 7-36038

  An object of the present invention is to provide a test method and a test apparatus for a pneumatic tire that can efficiently reproduce a tier similar to a tread tier generated in the market and can evaluate a tire tier resistance.

  In order to achieve the above object, the pneumatic tire testing method of the present invention is to assemble a test tire having a circumferential groove on a tread to a predetermined internal pressure, apply a predetermined load to the planar surface of the mounting table. The tread is grounded, and the rod-like protrusion fixed to the surface of the mounting table is covered with the circumferential groove across the grounding region and the non-grounding region of the testing tire with the mounting table, At least one of the test tire and the mounting table is rotated about a rotation axis that is substantially normal to the surface of the mounting table. Here, the substantially normal direction means a range of ± 5 degrees with respect to the normal direction.

  The pneumatic tire testing device of the present invention has a tire holding device for holding a rim-assembled test tire, and a flat surface for grounding the tread of the held test tire, and a rod-like protrusion on the surface. A fixed mounting table, and at least one of the held test tire and the mounting table is movable in a direction in which the tread of the held test tire is brought into contact with the surface of the mounting table, and a load is applied in that direction. In addition to being able to do so, at least one of the held test tire and the mounting table can be rotated around a rotation axis that is substantially in a direction normal to the surface of the mounting table.

  According to the test method for a pneumatic tire of the present invention, a test tire having a circumferential groove is assembled on the tread to obtain a predetermined internal pressure, and a predetermined load is applied to ground the tread on the planar surface of the mounting table. And at least one of the test tire and the mounting table in a state where the rod-like protrusion fixed to the surface of the mounting table is covered with a circumferential groove across the grounding region and the non-grounding region of the testing tire mounting table. Rotating the center of rotation about the surface of the mounting table and a rotation axis that is approximately normal, the projections can reproduce the tier similar to the tier generated in the market by applying external force to the tread, and the degree of the tier generated I can grasp it. As a result, the tear resistance can be evaluated efficiently, and a comparative evaluation of the tear resistance of tires having different specifications is also possible.

  According to the pneumatic tire testing apparatus of the present invention, the tire holding device that holds the rim-assembled test tire and the planar surface that contacts the tread of the held test tire are fixed, and the rod-shaped protrusion is fixed to the surface. A mounting table, and at least one of the held test tire and the mounting table can be moved in a direction in which the tread of the held test tire contacts the surface of the mounting table, so that a load can be applied in this direction. Therefore, a predetermined load can be applied by covering the rod-shaped protrusion on the surface of the mounting table with the circumferential groove of the test tire across the grounding region and the non-grounding region with the mounting table of the test tire. Since at least one of the test tire and the mounting table held in this state can be rotated around a rotation axis that is substantially normal to the surface of the mounting table, the rotation causes an external force to be applied to the tread of the test tire. It is possible to reproduce a tier similar to the tier generated in the market and to grasp the degree of the generated tier. As a result, the tear resistance can be evaluated efficiently, and a comparative evaluation of the tear resistance of tires having different specifications is also possible.

  Hereinafter, a test method and a test apparatus for a pneumatic tire according to the present invention will be described based on the embodiments shown in the drawings. FIG. 1 is a front view showing an overall outline of the test apparatus. In this figure, the line segment CL indicates the center line in the tire width direction, and the line segment HL indicates the tire axis. The test tire 1 is attached to a holding arm 6 of a tire holding device 5 in a state where a rim is assembled and a predetermined internal pressure is applied.

  The holding arm 6 is movable in the vertical direction and has a structure that can be fixed at a predetermined height. The holding arm 6 may be movable in the longitudinal direction of the arm, and by moving in the longitudinal direction, the position of the rotation axis of the rod-shaped protrusion 2 with respect to the test tire 1 can be easily changed.

  Below the test tire attached to the holding arm 6, a rotary elevating device 4 is arranged, and a flat plate-like mounting table 3 having a bar-like protrusion 2 having a rectangular vertical cross section on the surface is fixed to the upper part thereof.

  The rotary elevating device 4 can be raised and lowered by a hydraulic mechanism or the like, and can be rotated by a drive motor or the like with the normal direction of the surface of the mounting table 3 as a rotation axis. Not controlled by the control device. The rod-like protrusion 2 is detachable, and the rod-like protrusion 2 selected according to the test conditions is mounted and fixed on the surface of the mounting table 3.

  In carrying out the test, first, the test tire 1 and the rod-shaped protrusion 2 are set. When the tread of the test tire 1 contacts the surface of the mounting table 3, the test tire 1 and the rod-shaped protrusion 2 are positioned and fixed so as to cover the rod-shaped protrusion 2 with the circumferential groove 1b. Thereafter, the rotating / lifting device 4 is raised, the test tire 1 covers the rod-shaped protrusion 2 with the circumferential groove 1b, contacts the mounting table 3, and stops rising at a position where a predetermined load is applied. The height position is fixed.

  The load applied to the test tire 1 can be given by fixing the rotary lifting device 4 and lowering the holding arm 6, and at least one of the rotary lifting device 4 and the holding arm 6 moves in a direction close to each other. Then, a load may be applied.

  The state where the test tire 1 is grounded on the mounting table 3 is shown in FIGS. As shown in FIG. 2, the rod-like protrusion 2 is covered with the circumferential groove 1b in the front direction. The width of the rod-like protrusion 2 is equal to or less than the width of the circumferential groove 1b, and the protrusion height H is set according to the groove depth D of the circumferential groove 1b depending on the test conditions.

  As shown in FIG. 3, the rod-like protrusion 2 is disposed at a position across the grounding region C and the non-grounding region T of the test tire 1 in the side surface direction. In the grounding area C, the rib 1a is in a compressed state, and even if an external force is applied by rotating the rod-shaped protrusion 2, tearing hardly occurs, and the rod-shaped protrusion 2 straddles the grounding area C and the non-grounding area T. By arranging the rib 1a in the portion where the rib 1a is in the tensioned state, tearing is likely to occur. The length of the rod-shaped protrusion 2 can be appropriately determined so as to straddle the grounding region C and the non-grounding region T.

  After the above setting is completed, the rotary lifting device 4 is rotated at a predetermined speed to a predetermined angle. 4 (a) and 4 (b) show the state of the test tire 1 in contact with the rod-shaped protrusion 2 that rotates together with the mounting table 3 in the plane direction. A line segment HL in this figure indicates a vertical projection line of the tire axis line on the mounting table 3, and is hereinafter used as the tire axis line HL in the description. As shown in FIG. 4 (a), the tire is initially maintained until the rod-like protrusion 2 covered by the circumferential groove 1b of the test tire 1 reaches a predetermined rotation angle R as shown in FIG. 4 (b). It passes through the intersection of the width direction center line CL and the tire axis HL, and rotates about the surface of the mounting table 3 and the rotation axis P in the normal direction. In FIG. 4B, the rod-like protrusion 2 and the rib 1a are shown overlapping each other, but in reality, this portion of the rib 1a is deformed to generate a tear.

  In this embodiment, the lifting / lowering rotation device 4 rotates the rod-shaped protrusion 2 to apply an external force that generates a tear. However, the tire holding device 5 has a rotation function to rotate the test tire 1 to apply the external force. It can also be given. That is, an external force for generating a tear may be applied to the rib 1a by rotating either the mounting table 3 to which the rod-shaped protrusion 2 is fixed or the test tire 1.

  Further, although the rotation axis P is set as the normal direction of the surface of the mounting table 3, the range of ± 5 degrees from the normal direction is allowed because the reproducibility of the tier is not affected.

  The position of the rotation axis P is not limited to a position passing through the intersection of the tire width direction center line CL and the tire axis HL as shown in FIG. In order to efficiently reproduce the market tier of the tire mounted on the steer shaft, it is only necessary that the rotating shaft P be in the contact area with the mounting table 3 of the test tire 1.

  In FIG. 4, the number of the bar-shaped protrusions 2 is one. However, for example, two bar-shaped protrusions 2 may be provided at positions that are point-symmetric with respect to the intersection of the rotation axis P and the mounting table 3.

  In the test of the present invention, the protrusion height H of the rod-like protrusion 2 is preferably 30% or more and 120% or less of the groove depth D of the circumferential groove 1b covering the rod-like protrusion 2. Within this range, the tier can be reproduced with increased similarity to the tier generated in the market.

  It is preferable that the longitudinal cross-sectional shape of the rod-shaped protrusion 2 is a rectangle, and the angle of both edge corners 2a is 90 degrees or more and 120 or less. When this angle is less than 90 degrees, when an external force is applied by the rod-shaped protrusion 2, the corner 2a bites into the rib 1a too much, and when it exceeds 120 degrees, the rib 1a is deformed and easily escapes. It becomes difficult to reproduce the same tier.

  The load load of the test tire 1 is preferably 70% or more and 130% or less of the standard maximum load of the tire corresponding to the use conditions assumed in the market.

  Using a pneumatic tire with a rib pattern of 11R22.5 (standard maximum load 26.73 kN, standard maximum air pressure 700 kPa), load load 26.73 kN, air pressure 700 kPa, rotation angle R 45 °, rotation speed 50 deg. / Min, the length of the bar-shaped protrusion on the mounting table is 150 mm, the vertical cross-sectional shape is rectangular, the angle of both edges is 90 degrees, and the common condition is that the bar-shaped steel material is used, only the height of the protrusion As shown in Table 1, the durability against tiers was evaluated by changing to 5 types (Examples 1 to 5). The evaluation results are shown in Table 1. The evaluation items are the presence / absence of a tier and the similarity between the tier that occurs and the tier that occurs in the market.

  In the table, H indicates the protrusion height, and D indicates the groove depth of the circumferential groove that covers the rod-shaped protrusion. Therefore, if H / D is 20%, the protrusion is not in contact with the bottom surface of the circumferential groove, and if H / D is 140%, the protrusion is in contact with the bottom surface of the circumferential groove. Become.

[Tear occurrence]
If any kind of torn failure occurs on the tread rib, it is indicated by a circle.

[Similarity with market tier]
The tiers generated by the test were compared with the tiers generated in the market, the cases that are almost similar are indicated by circles, and the cases that are very similar are indicated by double circles.

In all of Examples 1 to 5, tiers were generated, and the generated tiers were similar to tiers generated in the market. In particular, when H / D was 30 to 120%, very similar tiers could be reproduced.
From this result, it is possible to efficiently reproduce the tiers that occur in the market, and to understand the degree of tiers that occur, so it is possible to reduce time and cost and to compare and evaluate tier resistance for tires with different specifications. It could be confirmed.

It is explanatory drawing which shows the whole outline | summary of the testing apparatus of this invention. In the test method of this invention, it is a longitudinal cross-sectional view which shows the state which the tread of the test tire grounded on the mounting base. FIG. 3 is a partially enlarged side view of FIG. 2. In the test method of this invention, it is explanatory drawing which shows the state which makes a test tire contact ground to the mounting base which has a rod-shaped protrusion, and rotates a rod-shaped protrusion in a plane direction.

Explanation of symbols

1 Test tire
1a rib
1b Circumferential groove 2 Rod-shaped protrusion
2a Corners on both edges of rod-shaped protrusions
DESCRIPTION OF SYMBOLS 3 Mounting stand 4 Rotation raising / lowering device 5 Tire holding device 6 Holding arm C Grounding area
T non-contact area P rotation axis R rotation angle CL tire width direction center line HL tire axis

Claims (7)

  A test tire having a circumferential groove on the tread is assembled with a rim to a predetermined internal pressure, a predetermined load is applied, the tread is grounded on the planar surface of the mounting table, and a rod-shaped fixed to the surface of the mounting table is provided. A protrusion is covered with the circumferential groove across a grounding region and a non-grounding region of the test tire with the mounting table, and at least one of the test tire and the mounting table is a surface of the mounting table. A test method for a pneumatic tire that rotates about a rotation axis that is substantially in the normal direction.   The method for testing a pneumatic tire according to claim 1, wherein the rotation shaft is in a contact area with the surface of the mounting table described above.   The method for testing a pneumatic tire according to claim 1 or 2, wherein a height of the protrusion is 30% or more and 120% or less of a groove depth of a circumferential groove covering the protrusion.   The method for testing a pneumatic tire according to any one of claims 1 to 3, wherein a vertical cross-sectional shape of the protrusion is rectangular, and an angle between both corners of the protrusion is 90 degrees or more and 120 degrees or less.   The test method for a pneumatic tire according to any one of claims 1 to 4, wherein a load applied to the test tire is 70% to 130% of a standard maximum load of the test tire.   A tire holding device that holds a test tire assembled with a rim, and a mounting table that has a flat surface for grounding the tread of the held test tire and has a rod-like protrusion fixed to the surface, and holds the test tire The tread of the test tire that holds at least one of the mounting table and the mounting table can be moved in a direction to make contact with the surface of the mounting table so that a load can be applied in the direction. A testing apparatus for a pneumatic tire, wherein at least one of the mounting table is rotatable about a rotation axis that is substantially normal to the surface of the mounting table.   The pneumatic tire testing device according to claim 6, wherein the protrusion is detachable.

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