JP2005297845A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of suppressing the eccentric wear of blocks by enhancing their stiffness when grounded. <P>SOLUTION: The pneumatic tire 1 has main grooves 2 and transverse grooves 3 in a tread part and a plurality of blocks 4 partitioned by these grooves 2 and 3. A first fitting part 41 is formed at one of the opposing groove walls of the adjoining blocks 4 while a second fitting part 42 is formed at the other groove wall, and the two fitting parts 41 and 42 are fitted together when the blocks 4 are grounded. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that can suppress the occurrence of uneven wear of the block by improving the rigidity of the block at the time of ground contact.

  In studless tires and the like, a subdivision process and a siping process are performed on the blocks constituting the tread portion in order to improve the traction performance. In such a configuration, since the rigidity of the block is lowered, there is a problem that uneven wear such as heel and toe wear occurs or steering stability is deteriorated.

  Regarding such problems, the techniques described in Patent Literature 1 and Patent Literature 2 are known for conventional pneumatic tires. In the pneumatic tire of Patent Document 1, sipes having terminal ends in the block are alternately arranged in the block. Moreover, in the pneumatic tire of patent document 2, the sipe which has the front-end | tip shape of a fork is arrange | positioned at the block. In the conventional pneumatic tire, the rigidity of the block is improved by improving the siping shape.

  However, in these conventional pneumatic tires, the small blocks divided into sipes support each other inside the block to support each other, but the rigidity of the block is improved because there is no small block to support at the end of the block. Does not improve. For this reason, there is a problem that a difference in rigidity occurs between the inside of the block and the end portion of the block, and uneven wear (particularly heel and toe wear) occurs.

JP-A-7-266810 JP-A-8-332811

  Therefore, the present invention has been made in view of the above, and an object of the present invention is to provide a pneumatic tire that can suppress the occurrence of uneven wear of the block by improving the rigidity of the block at the time of ground contact.

  In order to achieve the above object, a pneumatic tire according to the present invention is a pneumatic tire having a main groove and a lateral groove in a tread portion and having a plurality of blocks defined by these grooves, and adjacent blocks. The groove surface facing each other has a first fitting portion formed on one groove wall surface and a second fitting portion formed on the other groove wall surface, and the first fitting portion and the first fitting surface The two fitting portions are fitted when the block is grounded.

  In this pneumatic tire, when the first fitting portion and the second fitting portion of the opposing groove wall surfaces are fitted when the block is grounded, the block is supported and the block is prevented from falling. Thereby, since the rigidity of the block at the time of grounding is improved, there is an advantage that uneven wear of the block is suppressed.

  In the pneumatic tire according to the present invention, the first fitting portion and the second fitting portion are formed at positions close to the tread surface of the block.

  In this pneumatic tire, the first fitting portion and the second fitting portion are formed on the groove wall surface and at a position close to the tread surface of the block. In other words, the first fitting portion and the second fitting portion are formed on the groove wall surface at a position closer to the tread surface side than the middle. Thereby, there exists an advantage by which the fall of the block in the early stage of wear is suppressed effectively.

  In the pneumatic tire according to the present invention, the first fitting portion and the second fitting portion are formed at positions where they do not appear on the tread surface of the block.

  In this pneumatic tire, since the first fitting portion and the second fitting portion are formed at positions where they do not appear on the tread surface of the block, the situation where the fitting portion is scraped from the beginning due to wear of the block is suppressed. Thereby, since the function of the fitting portion is ensured for a considerable period from the initial wear of the block, there is an advantage that the collapse of the block is more effectively suppressed.

  In the pneumatic tire according to the present invention, the first fitting portion is a concave portion formed by recessing the groove wall surface, and the second fitting portion is a convex portion formed by projecting the groove wall surface. is there.

  In this pneumatic tire, the fitting portion is constituted by a concave portion or a convex portion. Such a fitting portion has an advantage that its molding is easy.

  In the pneumatic tire according to the present invention, the top area S2 of the second fitting portion is smaller than the opening area S1 of the first fitting portion.

  In this pneumatic tire, the top area S2 of the second fitting portion is configured to be smaller than the opening area S1 of the first fitting portion. There exists an advantage by which a two fitting part fits suitably and the fall of a block is suppressed effectively. In addition, it is more preferable that the top area S2 of the second fitting portion and the opening area S1 of the first fitting portion satisfy the relationship of 0.6 ≦ (S2 / S1) ≦ 0.9. Thereby, there exists an advantage by which a 1st fitting part and a 2nd fitting part fit more suitably, and the fall of a block is suppressed more effectively.

  Further, in the pneumatic tire according to the present invention, when the area of the block is projected onto the groove wall surface of the adjacent block, the projected area S3 is the groove wall surface of the adjacent block. It is comprised so that it may become larger than opening area S1 of the 1st fitting part formed in this.

  In this pneumatic tire, the projected area S3 of the block is configured to be larger than the opening area S1 of the first fitting portion. Therefore, when the block is grounded, the first fitting portion and the second fitting portion are arranged. The part fits suitably. Thereby, there exists an advantage by which the fall of a block is suppressed more effectively. It is more preferable that the projected area S3 of the block and the opening area S1 of the first fitting portion satisfy the relationship of 0.4 ≦ (S1 / S3). Thereby, at the time of grounding of a block, there exists an advantage by which a 1st fitting part and a 2nd fitting part fit more suitably, and the fall of a block is suppressed more effectively.

  In the pneumatic tire according to the present invention, the protruding height L2 of the second fitting portion has a dimension that is more than half of the distance G between the adjacent blocks.

  In this pneumatic tire, since the protrusion height L2 of the second fitting portion has a dimension that is more than half of the distance G between adjacent blocks, the first fitting portion and the second fitting portion are brought into contact with the block at the time of grounding. There exists an advantage by which a part fits suitably and the fall of a block is suppressed more effectively. Note that the recess depth L1 of the first fitting portion, the protrusion height L2 of the second fitting portion, and the distance G between adjacent blocks satisfy the relationship of G / 2 ≦ L2 <(G + L1). preferable. Thereby, at the time of grounding of a block, there exists an advantage by which a 1st fitting part and a 2nd fitting part fit more suitably, and the fall of a block is suppressed more effectively.

  In the pneumatic tire according to the present invention, the recess depth L1 of the first fitting portion is smaller than the protruding height L2 of the second fitting portion.

  In this pneumatic tire, since the recess depth L1 of the first fitting portion is configured to be smaller than the protruding height L2 of the second fitting portion, the first fitting is performed when the block is grounded. There exists an advantage by which a part and a 2nd fitting part fit stably, and the fall of a block is suppressed more effectively.

  In the pneumatic tire according to the present invention, the first fitting portion and the second fitting portion are formed at least on the groove wall surface on the lateral groove side of the block.

  In this pneumatic tire, the first fitting portion and the second fitting portion are formed on the lateral groove side of the block, that is, on the wall surface on the tire circumferential direction side. Thus, the blocks are coupled in the tire circumferential direction. As a result, since the falling of the block in the tire circumferential direction is suppressed, there is an advantage that the heel and toe wear of the block is effectively suppressed.

  In the pneumatic tire according to the present invention, the first fitting portion and the second fitting portion are formed between all the blocks arranged in the tire circumferential direction.

  In this pneumatic tire, the first fitting portion and the second fitting portion are formed between all the blocks in at least one row arranged in the tire circumferential direction. All the first fitting parts and the second fitting parts are fitted. Thereby, since the grounded block group supports each other, the collapse of the block is more effectively suppressed.

  According to the pneumatic tire according to the present invention, the first fitting portion and the second fitting portion of the opposing groove wall surfaces are fitted when the block is grounded, so that the block supports each other and collapse of the block is suppressed. Therefore, there is an advantage that the rigidity of the block at the time of ground contact is increased and uneven wear of the block is suppressed.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements of the embodiments described below include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  1 is a plan view showing a pneumatic tire according to a first embodiment of the present invention. 2 to 4 are a perspective view (FIG. 2), a plan view (FIG. 3), and a side view (FIG. 4) showing the block of the pneumatic tire shown in FIG. FIG. 5 is a side view showing the operation of the block shown in FIG.

  The pneumatic tire 1 includes a main groove 2 and a lateral groove 3 in a tread portion, and a plurality of blocks 4 defined by the grooves 2 and 3. In this pneumatic tire 1, fitting portions 41 and 42 are formed on the opposing groove wall surfaces between adjacent blocks 4 and 4. When the block 4 is grounded, the fitting portions 41 and 42 are fitted to each other, so that the block 4 is prevented from falling and the rigidity of the block 4 is improved.

  The fitting parts 41 and 42 of the block 4 are composed of a first fitting part 41 and a second fitting part 42 (see FIG. 2). The first fitting portion 41 is formed on one groove wall surface among the opposed groove wall surfaces between the adjacent blocks 4, 4, and is configured by a recess formed by recessing this groove wall surface. The 2nd fitting part 42 is formed in the other groove wall surface, and is comprised by the convex part formed by making this groove wall surface protrude. In addition, the fitting parts 41 and 42 which consist of such a recessed part and a convex part are easy to shape | mold. Further, the first fitting portion 41 and the second fitting portion 42 are formed on the side wall 3 side of the blocks 4 and 4, that is, on the groove wall surface on the tire circumferential direction side. Moreover, the 1st fitting part 41 and the 2nd fitting part 42 are comprised so that it may become a pair between the blocks 4 and 4 adjacent to a tire circumferential direction, and when it combines, it mutually fits. It has a shape and dimensions (see FIG. 3). Moreover, the 1st fitting part 41 and the 2nd fitting part 42 are provided in the middle of the groove wall surface (middle of block height) so that it may not appear on the tread of the block 4 (refer FIG. 4).

  In this pneumatic tire 1, when the tread portion (the tread surface of the block 4) is grounded and the block 4 is crushed by the contact pressure and swells in the width direction, the groove width is narrowed, so that the first of the adjacent blocks 4, 4 is The fitting part 41 and the second fitting part 42 are combined and fitted (see FIG. 5). Then, the blocks 4 and 4 support each other through the fitting portions 41 and 42, so that the collapse of the block 4 is suppressed.

  In the pneumatic tire 1, the first fitting portion 41 and the second fitting portion 42 are fitted when the block is grounded (see FIG. 5), and the block 4 is bidirectional in the height direction and the width direction. It is comprised so that it may engage with. With such a configuration, the fitting of the fitting portions 41 and 42 suppresses the positional deviation of the groove wall surface in the planar direction at the time of ground contact, particularly the positional deviation of the block 4 in the height direction. Thereby, the fall of the block 4 is suppressed more effectively.

  In the pneumatic tire 1, the first fitting portion 41 and the second fitting portion 42 are formed on the groove wall surface of the block 4 on the lateral groove 3 side. In such a configuration, the block 4 is coupled in the tire circumferential direction by fitting these fitting portions 41 and 42 at the time of grounding. Thereby, since the falling-down concerning the tire peripheral direction of the block 4 is suppressed, there exists an advantage by which the heel and toe wear of the block 4 is suppressed effectively.

  Moreover, in this pneumatic tire 1, the 1st fitting part 41 and the 2nd fitting part 42 are formed between all the blocks 4 and 4 arranged in the tire circumferential direction (refer FIGS. 1-4). ). In other words, the first fitting portion 41 is formed on one of the opposing groove wall surfaces and the second fitting portion 42 is formed on the other of all the groove wall surfaces of the blocks 4 and 4 adjacent in the tire circumferential direction. Yes. In such a configuration, all the first fitting parts 41 and the second fitting parts 42 between the grounded groups of blocks 4 are fitted, and these groups of blocks 4 function as if they are one rib. As a result, the group of blocks 4 that are grounded together support each other, and the collapse of the blocks 4 is more effectively suppressed.

  According to this pneumatic tire 1, since the fitting of the fitting parts 41 and 42 of the block 4 is prevented from being brought into contact with each other at the time of grounding, the block 4 is prevented from falling down, so that the rigidity of the block 4 at the time of grounding is increased. The ground contact area of the tread portion is maintained. Thereby, the traction performance and steering stability of the tire are improved, and there is an advantage that uneven wear (particularly, heel and toe wear) of the block 4 is suppressed.

  In the pneumatic tire 1, the fitting portions 41 and 42 are formed on the groove wall surface and at a position close to the tread surface (the surface of the tread portion) of the block 4 (see FIG. 4). Such a configuration is preferable in that the collapse of the block 4 at the initial stage of wear is effectively suppressed. Specifically, it is preferable that the fitting portions 41 and 42 are formed on the groove wall surface at a position closer to the tread surface side than the middle. Further, it is more preferable that the fitting portions 41 and 42 are formed on the groove wall surface at a position of 50 [%] or more of the height of the block 4.

  However, the present invention is not limited to this, and the fitting portions 41 and 42 may be formed at any position on the groove wall surface. For example, the fitting portions 41 and 42 are preferably formed on the groove wall surface at the position where the block 4 swells most when the block 4 is crushed at the time of grounding. Thereby, since the fitting parts 41 and 42 become easy to fit when the block 4 is crushed, there exists an advantage by which the fall of the block 4 is suppressed more effectively.

  Moreover, in this pneumatic tire 1, it forms so that the fitting parts 41 and 42 may not appear on the tread of the block 4 (refer FIG. 4). In such a configuration, the situation in which the fitting portions 41 and 42 are scraped from the beginning due to wear of the block 4 is suppressed, so that the function of the fitting portions 41 and 42 is ensured for a considerable period from the initial wear to the middle of the block 4. Is done. Moreover, since the fitting of the fitting parts 41 and 42 concerning the height direction of the block 4 is ensured, position shift or slippage between the groove wall surfaces in the height direction is suppressed. Thereby, there exists an advantage by which the fall of the block 4 is suppressed more effectively. However, the present invention is not limited to this, and the fitting portions 41 and 42 may be formed so as to appear on the tread surface of the block 4 (not shown).

  Even if the fitting portions 41 and 42 do not appear on the tread surface of the block 4 at the beginning, the fitting portions 41 and 42 appear on the tread surface of the block 4 due to wear of the block 4. However, at a stage where the block 4 is worn to some extent, the height of the block 4 is reduced, so that the rigidity of the block 4 is improved. Therefore, at this stage, the function of the fitting portions 41 and 42 becomes unnecessary, and no problem occurs.

  Moreover, in this pneumatic tire 1, the 2nd fitting part 42 is comprised by the substantially square pillar-shaped convex part, and the 1st fitting part 41 is comprised by the recessed part corresponding to this convex part (FIG. 1 to FIG. 5). Such a structure is firmly assembled in the plane direction of the groove wall surface (the height direction and the width direction of the block 4) when these fitting portions 41 and 42 are fitted, and the collapse of the block 4 is effectively suppressed. This is preferable.

  However, the present invention is not limited to this, and the shapes of the first fitting portion 41 and the second fitting portion 42 can be selected within a range obvious to those skilled in the art based on these functions and ease of processing. For example, the 2nd fitting part 42 consists of convex parts which have other prismatic shape, cylinder shape, weight shape, hemispherical shape, and other shapes, and the 1st fitting part 41 is constituted by a crevice corresponding to this convex part. (Not shown).

  FIG. 6 is a table showing the results of the performance test of the pneumatic tire according to Example 2 of the present invention. In the pneumatic tire 1 of the second embodiment, the same components as those of the pneumatic tire 1 of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In this pneumatic tire 1, the distance between the blocks 4, 4 (groove width of the lateral groove 3) G is 6 [mm], the depth L1 of the first fitting portion 41 is 1 [mm], and the second fitting portion 42. The height L2 is 4 [mm] (see FIGS. 3 and 4). The groove depths of the main groove 2 and the lateral groove 3 are both 18.5 [mm].

  In addition, the hollow depth L1 of the first fitting portion 41 is the depth of the first fitting portion 41 with respect to the groove wall surface, and means the amount of depression from the tread edge when the tread portion is viewed in plan. The protrusion height L2 of the second fitting portion 42 is the height of the second fitting portion 42 with respect to the groove wall surface, and means the amount of protrusion from the tread edge when the tread portion is viewed in plan. The distance G between the blocks 4 and 4 is also the groove width between the blocks 4 and 4.

  In the performance test shown in FIG. 6, the pneumatic tire 1 has a tire size of 11R22.5 14PR, is assembled with a rim according to JATMA normal conditions, and is loaded with a maximum internal pressure and a maximum load. The pneumatic tire 1 was tested for (1) uneven wear resistance and (2) braking performance (braking distance).

  (1) In the uneven wear resistance test, a vehicle equipped with pneumatic tires 1 was run on a paved road for 30,000 [km], and an index evaluation was performed on the amount of heel-and-toe wear of block 4 Went. In (2) braking performance test, braking was started for a vehicle equipped with the pneumatic tire 1 when traveling at 40 [km / h], and the braking distance was measured to evaluate the index. The braking performance test was performed when the road surface condition was dry (road surface temperature 25 [degrees]) and snow (pressed snow road. Road surface temperature 0 [degrees]). In addition, these index evaluation is displayed as a reference | standard (100) in a prior art example, and, as for all, it is so preferable that a numerical value is large.

  As shown in FIG. 6, the pneumatic tire 1 has uneven wear resistance and braking performance (dry and snow) compared to a conventional pneumatic tire (conventional example) that does not have the fitting portions 41 and 42. It can be seen that both are improved.

  FIG. 7 is an explanatory view showing a pneumatic tire block according to Embodiment 3 of the present invention. FIG. 8 is a table showing the results of the performance test of the pneumatic tire depicted in FIG. In the pneumatic tire according to the third embodiment, the same components as those in the pneumatic tire 1 of the first embodiment and the second embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the pneumatic tire 1, the top area S2 of the second fitting portion 42 is configured to be smaller than the opening area S1 of the first fitting portion 41 (see FIG. 7). Further, the second fitting portion 42 has a top area S2 that can be urged to the first fitting portion 41 stably at the time of fitting. Specifically, the opening area S1 of the first fitting portion 41 and the top area S2 of the second fitting portion 42 may satisfy the relationship of 0.6 ≦ (S2 / S1) ≦ 0.9. preferable. Thereby, when the block 4 is grounded, the first fitting portion 41 and the second fitting portion 42 are suitably fitted, and there is an advantage that the collapse of the block 4 is effectively suppressed.

  In the performance test shown in FIG. 8, the pneumatic tire 1 has a tire size of 11R22.5 14PR, is assembled with a rim in accordance with JATMA normal conditions, and is loaded with a maximum internal pressure and a maximum load. In this performance test, a braking performance test (dry) is performed by changing the value of the opening area S1 of the first fitting portion 41 and the value of the top area S2 of the second fitting portion 42, and the pneumatic tire 1 The braking performance was evaluated. The test method for this braking performance test is the same as that in the second embodiment.

  As shown in FIG. 8, it can be seen that the pneumatic tire 1 has improved braking performance as compared with a conventional pneumatic tire (conventional example) that does not have the fitting portions 41 and 42. Further, when the opening area S1 of the first fitting portion 41 and the top area S2 of the second fitting portion 42 satisfy the relationship of 0.6 ≦ (S2 / S1) ≦ 0.9, higher braking performance. (See Invention Examples 1, 3, 4, and 5).

  FIGS. 9-1 and FIGS. 9-2 are explanatory drawings which show the block of the pneumatic tire concerning Example 4 of this invention. FIG. 10 is a table showing the results of the performance test of the pneumatic tire depicted in FIGS. 9-1 and 9-2. In the pneumatic tire 1 of the fourth embodiment, the same components as those of the pneumatic tire 1 of the first to third embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  In this pneumatic tire 1, when the block 4 is projected onto the groove wall surface of the adjacent block 4, the projected area S 3 is larger than the opening area S 1 of the first fitting portion 41 when the area is defined as a projected area S 3. It is comprised so that it may become large (refer FIG. 9-1 and FIG. 9-2). Specifically, it is preferable that the projected area S3 of the block 4 and the opening area S1 of the first fitting portion 41 satisfy the relationship of 0.4 ≦ (S1 / S3). Thereby, when the block 4 is grounded, the first fitting portion 41 and the second fitting portion 42 are suitably fitted, and there is an advantage that the falling of the block 4 is more effectively suppressed. The projected area S3 is equal to the area of the groove wall surface of the block 4 when the adjacent blocks 4 and 4 are linearly arranged (see FIG. 9-1), and the adjacent blocks 4 and 4 are oblique. Is equal to the area of the projected block 4 (see FIG. 9-2).

  In the performance test shown in FIG. 10, the pneumatic tire 1 has a tire size of 11R22.5 14PR, is rim-assembled according to JATMA normal conditions, and is loaded with a maximum internal pressure and a maximum load. In this performance test, the braking performance test is performed by changing the value of the opening area S1 of the first fitting portion 41 and the value of the projected area S3 of the block 4, and the braking performance (dry) of the pneumatic tire 1 is evaluated. Went.

  The test method for this braking performance test is the same as that in the second embodiment. In this braking performance test, the opening area S1 of the first fitting portion 41 and the top area S2 of the second fitting portion 42 are configured to satisfy the relationship (S2 / S1) = 0.9. Yes.

  As shown in FIG. 10, it can be seen that this pneumatic tire 1 has improved braking performance compared to a conventional pneumatic tire (conventional example) that does not have the fitting portions 41 and 42. It can also be seen that higher braking performance can be obtained when the projected area S3 of the block 4 and the opening area S1 of the first fitting portion 41 satisfy the relationship of 0.4 ≦ (S1 / S3) ( (See Invention Examples 1, 7, and 8).

  FIG. 11 is a table showing the results of the performance test of the pneumatic tire according to Example 5 of the present invention. In the pneumatic tire 1 of the fifth embodiment, the same components as those of the pneumatic tire 1 of the first to fourth embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  In this pneumatic tire 1, the protruding height L <b> 2 of the second fitting portion is configured to have a dimension that is at least half the distance G between the adjacent blocks 4 and 4. Specifically, the recess depth L1 of the first fitting portion 41, the protruding height L2 of the second fitting portion, and the distance G between the adjacent blocks 4 and 4 are G / 2 ≦ L2 <(G + L1). ) (See FIGS. 2 and 3). With this configuration, when the block 4 is grounded, the first fitting portion 41 and the second fitting portion 42 are suitably fitted, and there is an advantage that the collapse of the block 4 is more effectively suppressed. .

  In the performance test shown in FIG. 11, the pneumatic tire 1 has a tire size of 11R22.5 14PR, is rim-assembled according to JATMA normal conditions, and is loaded with a maximum internal pressure and a maximum load. In this performance test, the value of the depth L1 of the first fitting portion 41 is fixed to 1 [mm], the value of the protrusion height L2 of the second fitting portion 42 is changed, and a braking performance test is performed. The braking performance (dry) of the pneumatic tire 1 was evaluated.

  The test method for this braking performance test is the same as that in the second embodiment. In this braking performance test, the opening area S1 of the first fitting portion 41 and the top area S2 of the second fitting portion 42 are configured to satisfy the relationship (S2 / S1) = 0.9. Yes. Further, the projected area S3 of the block 4 and the opening area S1 of the first fitting portion 41 are configured to satisfy the relationship of (S1 / S3) = 0.5. The groove depth is 18.5 [mm].

  As shown in FIG. 11, it can be seen that the pneumatic tire 1 has improved braking performance as compared with a conventional pneumatic tire (conventional example) that does not have the fitting portions 41 and 42. Further, the depth L1 of the first fitting portion 41, the protrusion height L2 of the second fitting portion, and the distance G between the opposing blocks 4 and 4 are such that G / 2 ≦ L2 <(G + L1). It can be seen that higher braking performance can be obtained when the conditions are satisfied (see Invention Examples 1, 10, and 11).

  FIG. 12 is a table showing the results of the performance test of the pneumatic tire according to Example 6 of the present invention. In the pneumatic tire 1 of the sixth embodiment, the same components as those of the pneumatic tire 1 of the first to fifth embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  The pneumatic tire 1 is configured such that the recess depth L1 of the first fitting portion 41 is smaller than the protruding height L2 of the second fitting portion 42 (see FIGS. 2 and 3). That is, the recess depth L1 of the first fitting portion 41 and the protrusion height L2 of the second fitting portion 42 satisfy the relationship 0 <L1 <L2. With such a configuration, there is an advantage that the first fitting portion 41 and the second fitting portion 42 are stably fitted when the block 4 is grounded, and the collapse of the block 4 is more effectively suppressed. is there.

  In the performance test shown in FIG. 12, the pneumatic tire 1 has a tire size of 11R22.5 14PR, is rim-assembled according to JATMA normal conditions, and is loaded with a maximum internal pressure and a maximum load. In this performance test, the value of the protrusion height L2 of the second fitting portion 42 is fixed to 4 [mm], the value of the recess depth L1 of the first fitting portion 41 is changed, and a braking performance test is performed. The braking performance (dry) of the pneumatic tire 1 was evaluated.

  The test method for this braking performance test is the same as that in the second embodiment. In this braking performance test, the opening area S1 of the first fitting portion 41 and the top area S2 of the second fitting portion 42 are configured to satisfy the relationship (S2 / S1) = 0.9. Yes. Further, the projected area S3 of the block 4 and the opening area S1 of the first fitting portion 41 are configured to satisfy the relationship of (S1 / S3) = 0.5. The groove depth is 18.5 [mm].

  As shown in FIG. 12, this pneumatic tire 1 has improved braking performance compared to a pneumatic tire (Comparative Example 4) in which the depth L1 of the first fitting portion 41 is 0 [mm]. (See Invention Examples 1, 12, and 13).

  13 and 14 are explanatory views showing blocks of a pneumatic tire according to Example 7 of the present invention. In these drawings, the same components as those of the pneumatic tire 1 of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the pneumatic tire 1, the first fitting portion 41 and the second fitting portion 42 are formed to have the same width as the width of the block 4. In such a configuration, when the first fitting portion 41 and the second fitting portion 42 are fitted when the block 4 is grounded, the fitting portions 41 and 42 are in the height direction (groove depth) of the block 4. The block 4 is prevented from falling down (not shown, see FIG. 5). As a result, the rigidity of the block 4 at the time of ground contact is enhanced, and the ground contact area of the tread portion is maintained, so that the traction performance and steering stability of the tire are improved and uneven wear of the block 4 is suppressed. There is.

  FIG. 15 is an explanatory view showing a pneumatic tire block according to Embodiment 8 of the present invention. In the figure, the same components as those of the pneumatic tire 1 of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the pneumatic tire 1, the first fitting portion 41 and the second fitting portion 42 are also formed on the groove wall surface of the block 4 on the main groove 2 side. That is, the adjacent blocks 4, 4 have the first fitting portion 41 or the second fitting portion 42 on the groove wall surface on the main groove 2 side (and the groove wall surface on the lateral groove 3 side), and the main groove Between the blocks 4 and 4 facing each other with 2 (and the lateral groove 3) interposed therebetween, these fitting portions 41 and 42 are configured as a pair so as to be fitted to each other.

  In such a configuration, when the block 4 is grounded, the first fitting portion 41 and the second fitting portion 42 are fitted on the groove wall surfaces on both the main groove 2 side and the lateral groove 3 side (not shown). . Therefore, in such a configuration, the blocks 4 are combined with each other in the circumferential direction and the width direction of the tread portion, so that the collapse of the blocks 4 is more effectively suppressed. In particular, the collapse of the block 4 in the width direction is suppressed. As a result, the rigidity of the block 4 at the time of ground contact is enhanced, and the ground contact area of the tread portion is maintained, so that the traction performance and steering stability of the tire are improved and uneven wear of the block 4 is suppressed. There is.

  As described above, the pneumatic tire according to the present invention is useful in that it can suppress the occurrence of uneven wear of the block by improving the rigidity of the block at the time of ground contact.

It is a top view which shows the pneumatic tire concerning Example 1 of this invention. It is a perspective view which shows the block of the pneumatic tire described in FIG. It is a top view which shows the block of the pneumatic tire described in FIG. It is a side view which shows the block of the pneumatic tire described in FIG. It is a side view which shows the effect | action of the block described in FIG. It is a graph which shows the result of the performance test of the pneumatic tire concerning Example 2 of this invention. It is explanatory drawing which shows the block of the pneumatic tire concerning Example 3 of this invention. It is a chart which shows the result of the performance test of the pneumatic tire described in FIG. It is explanatory drawing which shows the block of the pneumatic tire concerning Example 4 of this invention. It is explanatory drawing which shows the block of the pneumatic tire concerning Example 4 of this invention. 10 is a chart showing the results of a performance test of the pneumatic tire depicted in FIG. 9. It is a graph which shows the result of the performance test of the pneumatic tire concerning Example 5 of this invention. It is a graph which shows the result of the performance test of the pneumatic tire concerning Example 6 of this invention. It is explanatory drawing which shows the block of the pneumatic tire concerning Example 7 of this invention. It is explanatory drawing which shows the block of the pneumatic tire concerning Example 7 of this invention. It is explanatory drawing which shows the block of the pneumatic tire concerning Example 8 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Main groove 3 Horizontal groove 4 Block 41 1st fitting part 42 2nd fitting part S1 Opening area S2 of fitting part S2 Top area S3 Projection area G Distance between blocks

Claims (10)

A pneumatic tire having a main groove and a lateral groove in a tread portion and having a plurality of blocks defined by these grooves,
A first fitting portion is formed on one groove wall surface and a second fitting portion is formed on the other groove wall surface, and the first fitting portion is formed on an opposite groove wall surface of an adjacent block. The pneumatic tire is characterized in that the second fitting portion is fitted when the block is grounded.   The pneumatic tire according to claim 1, wherein the first fitting portion and the second fitting portion are formed at a position close to a tread surface of the block.   The pneumatic tire according to claim 1 or 2, wherein the first fitting portion and the second fitting portion are formed at positions where they do not appear on the tread surface of the block.   The first fitting portion is a concave portion formed by recessing the groove wall surface, and the second fitting portion is a convex portion formed by projecting the groove wall surface. Pneumatic tire described in 2.   The pneumatic tire according to claim 4, wherein a top area S2 of the second fitting portion is smaller than an opening area S1 of the first fitting portion. When the area is projected area S3 when the block is projected onto the groove wall surface of the adjacent block,
The pneumatic tire according to claim 4 or 5, wherein the projected area S3 is configured to be larger than an opening area S1 of a first fitting portion formed on a groove wall surface of the adjacent block.   The pneumatic tire according to any one of claims 4 to 6, wherein a protruding height L2 of the second fitting portion has a dimension that is at least half of a distance G between the adjacent blocks.   The pneumatic tire according to any one of claims 4 to 7, wherein a recess depth L1 of the first fitting portion is smaller than a protruding height L2 of the second fitting portion.   The pneumatic tire according to any one of claims 1 to 8, wherein the first fitting portion and the second fitting portion are formed at least on a groove wall surface on a lateral groove side of the block.   The pneumatic according to any one of claims 1 to 9, wherein the first fitting portion and the second fitting portion are formed between all the blocks in at least one row arranged in a tire circumferential direction. tire.

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