JP5519991B2 - Running body with lugs - Google Patents

Description

  The present invention relates to a traveling body with a lug. More specifically, the present invention relates to a traveling body with a lug that can be attached to an agricultural machine and a light civil engineering construction machine that travel in wetlands, soft ground, and the like.

  A working machine such as an agricultural machine and a light civil engineering construction machine is equipped with a traveling body with a lug in consideration of workability in wet fields and soft ground. The traveling body includes a lug tire and a lug crawler.

  The tread of a tire with lugs includes a main body and a large number of lugs protruding outward in the radial direction from the main body. The lug extends rearward in the rotational direction from the vicinity of the equator plane toward the end of the tread. The lugs are alternately arranged on the left and right in the rotation direction. The rug sinks into the mud. Rug scratches mud. Lugs can contribute to tire traction.

  When the working machine travels in the field, mud adheres to the lug-equipped tire. If mud adheres to the bottom of the lug located between the lugs, the traction of the tire is reduced. Excessive mud deposits cause the machine to stack.

  Since the tire is rotating, mud adhering to the tire may be lifted upward. If the machine is a rice transplanter and mud falls from the tire, the seedlings that have just been planted may be covered with mud, broken, and fallen.

  The machine may travel on a paved road when moving the field. In this case, the road becomes dirty with mud adhering to the tire. If mud remains attached to the tire, it may be difficult to remove the mud from the tire during car washing.

  In view of such a situation, various investigations have been made on the reduction of mud adhesion of a traveling body with a lug. An example of this study is disclosed in Japanese Patent Application Laid-Open No. 2007-161192. In the traveling body with a lug described in this publication, a large number of protrusions are arranged at predetermined intervals on the lug bottom.

JP 2007-161192 A

  The field before plowing (uncultivated land) is cultivated with a cultivator. Uncultivated mud is hard. When traveling on uncultivated land with the lagging traveling body described in the above publication, there is little mud adhering to the lagging traveling body. On uncultivated land, this lagging traveling body can effectively reduce mud adhesion.

  The cultivator that has finished the cultivation work moves to another field. During this movement, the cultivator may run on a field that has just been cultivated (already cultivated land).

  The mud is crushed finely by tillage. Cultivated land is more flexible than uncultivated land. For this reason, when traveling on already cultivated land with this cultivator, the mud sinks between the protrusions and the protrusions, and the mud adheres to the lug bottom of the traveling body with lugs. This traveling body with a lag has a problem that it is not possible to sufficiently reduce the adhesion of mud in already cultivated land.

  An object of the present invention is to provide a traveling body with a lug excellent in the effect of reducing adhesion of mud.

  The traveling body with a lug according to the present invention includes a tread having a main body, a plurality of lugs protruding from the main body, and a lug bottom. The lug bottom includes a group of protrusions. This projection group is composed of a number of projections protruding from the reference surface of the lug bottom. These protrusions are arranged at intervals. This interval is 1.5 mm or more and less than 3.0 mm.

Preferably, in the traveling body with lugs, the interval is 2.0 mm or less. Preferably, in the traveling body with a lug, the height of the protrusion is 6 mm or more and 10 mm or less. Preferably, in the traveling body with a lug, an angle formed by the protrusion with respect to the reference surface is not less than 80 ° and not more than 90 °. Preferably, in the traveling body with a lug, the cross-sectional area of the protrusion is 0.8 mm ² or more and 7.1 mm ² or less. Preferably, in the traveling body with a lug, the protrusion is formed in a columnar shape. The outer diameter of this protrusion is 1 mm or more and 3 mm or less.

  Preferably, in the traveling body with a lug, the lug bottom further includes a sub-projection group outside the projection group. This sub-projection group consists of a large number of sub-projections protruding from the reference surface of the lug bottom. The height of each sub-projection is lower than the height of the projection.

  Preferably, in this traveling body with a lug, the height of the sub-projection located on the projection group side is lower than the height of the projection. The height of the other sub-projections located outside the sub-projections is lower than the height of the sub-projections.

  In the traveling body with a lag according to the present invention, adhesion of mud is suppressed not only in uncultivated land but also in already cultivated land. This traveling body with a lug is excellent in the effect of reducing adhesion of mud.

FIG. 1 is a development view showing a part of a tire with lugs as a running body with lugs according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is an enlarged cross-sectional view showing a part of the protrusion group of FIG. FIG. 5 is an enlarged cross-sectional view showing a part of the sub-projection group of FIG. FIG. 6 is an enlarged cross-sectional view showing a state where the tire of FIG. 1 is in contact with the ground.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  The lug-equipped tire 2 shown in FIGS. 1 and 2 as a running body with a lug is attached to an agricultural machine. Examples of the agricultural machine include a tractor, a binder, a harvester, a combine, a rice transplanter, a transporter, and a tiller. The tire 2 may be mounted on a light civil engineering construction machine such as a trencher and a dozer.

  In FIG. 1, the left-right direction is the axial direction of the tire 2. The direction indicated by the arrow A is the rotation direction of the tire 2. In FIG. 2, the vertical direction is the radial direction of the tire 2, and the horizontal direction is the axial direction of the tire 2. An alternate long and short dash line CL in FIGS. 1 and 2 represents the equator plane of the tire 2.

  The tire 2 includes a tread 4, a sidewall 6, a bead 8, a carcass 10, and a belt 12. Although not shown, the tire 2 includes a tube. This tube is filled with air.

  The tread 4 is made of a crosslinked rubber. The tread 4 has a shape protruding outward in the radial direction. The tread 4 includes a main body 14, a plurality of lugs 16, and a plurality of lug bottoms 18.

  The plurality of lugs 16 extend rearward in the rotational direction from the vicinity of the equator plane toward the end of the tread 4. These lugs 16 are alternately arranged on the left and right in the rotation direction. Each of these lugs 16 protrudes radially outward from the main body 14. This lug 16 sinks into the mud constituting the farm field and scratches this mud. This lug 16 can contribute to the traction of the tire 2. The shape, interval, height, and the like of the lugs 16 are appropriately determined in consideration of the specifications of the tire 2 and the like.

  The plurality of lug bottoms 18 are alternately arranged on the left and right in the rotation direction. As shown in FIG. 1, each lug bottom 18 is located between the lugs 16 in the rotational direction. In the tire 2, the plurality of lugs 16 and the plurality of lug bottoms 18 are alternately arranged in the rotation direction. The number of lugs 16 provided on the tread 4 is equal to the number of lug bottoms 18.

  The sidewall 6 extends substantially inward in the radial direction from the end of the tread 4. The sidewall 6 is made of a crosslinked rubber. The sidewall 6 absorbs an impact from the road surface by bending. Furthermore, the sidewall 6 prevents the carcass 10 from being damaged.

  The bead 8 is located substantially inward of the sidewall 6 in the radial direction. The bead 8 includes a core 20 and an apex 22 that extends radially outward from the core 20. The core 20 has a ring shape. The core 20 is formed by winding a non-shrinkable wire. Typically, a steel wire is used for the core 20. The apex 22 is tapered outward in the radial direction. The apex 22 is made of a highly hard crosslinked rubber. In addition, this bead 8 may be composed of only the core 20. In this case, the bead 8 does not include the apex 22.

  The carcass 10 includes a first carcass ply 24 and a second carcass ply 26. The first carcass ply 24 and the second carcass ply 26 are bridged between the beads 8 on both sides, and are along the inside of the tread 4 and the sidewall 6. The first carcass ply 24 and the second carcass ply 26 are folded around the core 20 from the inner side to the outer side in the axial direction.

  Although not shown, the first carcass ply 24 and the second carcass ply 26 are composed of a large number of cords arranged in parallel and a topping rubber. The absolute value of the angle formed by each cord with respect to the equator plane is usually 10 ° or more and 60 ° or less. In other words, the carcass 10 has a bias structure. The cord is usually made of organic fibers. Examples of preferable organic fibers include polyester fibers, nylon fibers, rayon fibers, polyethylene naphthalate fibers, and aramid fibers.

  The belt 12 is located on the radially outer side of the carcass 10. The belt 12 is laminated with the carcass 10. The belt 12 reinforces the carcass 10. The tire 12 may not be provided with the belt 12.

  Although not shown, the belt 12 includes a plurality of cords arranged in parallel and a topping rubber. Each cord is inclined with respect to the equator plane. The absolute value of the tilt angle is not less than 10 ° and not more than 60 °. A preferred material for the cord is organic fiber. Examples of the organic fiber include polyester fiber, nylon fiber, rayon fiber, polyethylene naphthalate fiber, and aramid fiber. From the viewpoint of versatility, the cord material is preferably nylon fiber.

  FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 3 shows a lug bottom 18 between the lug 16a and another lug 16b located on the rear side in the rotational direction of the lug 16a. The lug bottom 18 includes a projection group 30 and a sub projection group 32. The protrusion group 30 is located inside the sub protrusion group 32. Although not shown, the projection group 30 is surrounded by the sub-projection group 32.

  FIG. 4 shows a part of the protrusion group 30. The protrusion group 30 includes a large number of protrusions 34. These protrusions 34 are arranged at a predetermined interval.

  These protrusions 34 protrude substantially outward in the radial direction from the reference surface 36 of the lug bottom 18. These protrusions 34 have the same height.

  Each protrusion 34 includes a main body 38 and a base 40. The main body 38 has a cylindrical shape. The cross-sectional shape of the main body 38 is a circle. The front end portion of the main body 38 is rounded. The root 40 is configured such that its outer diameter gradually increases toward the reference surface 36. This root 40 can contribute to preventing the protrusion 34 from being cut.

  FIG. 5 shows a part of the sub-projection group 32. The sub-projection group 32 is located outside the projection group 30. Although not shown, the sub-projection group 32 is located around the projection group 30.

  The sub projection group 32 includes a large number of sub projections 42. These sub-projections 42 are arranged at a predetermined interval.

  In the tire 2, a large number of sub-projections 42 constituting the sub-projection group 32 are arranged in two rows along the projection group 30. These sub-projections 42 may be arranged in three or more rows along the projection group 30.

  These sub-projections 42 protrude from the reference surface 36 of the lug bottom 18 substantially outward in the radial direction. The heights of these sub-projections 42 are lower than the height of the projections 34.

  As shown in FIG. 5, the height of the auxiliary protrusion 42 a located on the protrusion group 30 side is lower than the height of the protrusion 34. The height of the other sub-projections 42b located outside the sub-projections 42a is lower than the height of the sub-projections 42a. In the tire 2, each sub-projection 42 is configured so that its height gradually decreases from the projection group 30 side toward the outside.

  The sub-projection 42 includes a main body 44 and a base 46. The main body 44 is cylindrical. The cross-sectional shape of the main body 44 is a circle. The front end portion of the main body 44 is rounded. The base 46 is configured such that its outer diameter gradually increases toward the reference surface 36. The root 46 can contribute to preventing the sub-projection 42 from being cut.

  FIG. 6 is an enlarged cross-sectional view showing a state where the tire 2 of FIG. 1 is in contact with the ground 48. What is indicated by an arrow A is the rotation direction of the tire 2. As described above, the tire 2 is used by being mounted on an agricultural machine. The tire 2 can support an agricultural machine. The tire 2 in use receives a load in the direction indicated by the arrow B. For this reason, when the tire 2 rotates and the lug bottom 18 comes into contact with the ground 48, the protrusion 34 is deformed. As shown in the drawing, the protrusion 34 falls to the rear side in the rotation direction. The tip portion of the protrusion 34 abuts on the side surface of another protrusion 34 adjacent to the protrusion 34. By this contact, a space is formed between the ground 48 and the reference surface 36 of the lug bottom 18. In the tire 2, the large number of protrusions 34 constituting the protrusion group 30 cover the reference surface 36 of the lug bottom 18, so that the contact between the reference surface 36 and the ground 48 is effectively prevented.

  Agricultural machinery may plow uncultivated land and then travel to already cultivated land to move to other fields. Since the mud is crushed finely by tillage, the cultivated land is more flexible than the uncultivated land. In the tire 2, an interval between the protrusion 34 and another protrusion 34 closest to the protrusion 34 (hereinafter, an interval between the protrusions 34) is appropriately set so that a large number of protrusions 34 constituting the protrusion group 30 are arranged densely. It has been adjusted. In the tire 2, mud mud is effectively reduced between the protrusions 34 in the already cultivated land as well as in the uncultivated land. In the tire 2, mud is not easily clogged between the protrusions 34. In the tire 2, adhesion of mud is effectively suppressed. This tire 2 is excellent in the effect of reducing adhesion of mud.

  When the tire 2 rotates and the lug bottom 18 moves away from the ground 48, the load is removed and the protrusion 34 is restored. Even if the tire 2 mud adheres, the mud is effectively removed from the tire 2 by the restoring force of the protrusion 34.

  In the tire 2, since mud adherence is suppressed, the lugs 16 continue to scrape the mud stably. In the tire 2, excellent traction is maintained.

  In the tire 2, adhesion of mud is suppressed, so that even when an agricultural machine that has finished its work travels on a paved road for movement, contamination of the paved road with mud is effectively prevented.

  In this tire 2, since the position where the mud is separated from the tire 2 is low, damage of the seedling or the like that has just been planted due to the falling mud is prevented.

In the tire 2, the protrusion 34 satisfies the following conditions.
(1) The height of the protrusion 34 is 6 mm or more and 10 mm or less.
(2) The interval between the protrusions 34 is 1.5 mm or more and less than 3.0 mm.
(3) The angle formed by the protrusion 34 with respect to the reference surface 36 of the lug bottom 18 is not less than 80 ° and not more than 90 °.
(4) The cross-sectional area of the protrusion 34 is 0.8 mm ² or more and 7.1 mm ² or less.

  In FIG. 4, the solid line BM represents the reference surface 36 of the lug bottom 18. A double arrow HM represents the height from the reference surface 36 to the tip 50 of the protrusion 34. This height HM is the height of the protrusion 34. A double arrow WM represents the interval between the protrusions 34. The interval WM is obtained by measuring the distance between the main body 38a of the protrusion 34 and the main body 38b of the other protrusion 34 closest to the protrusion 34. An alternate long and short dash line AM represents the axis of the protrusion 34. The angle α represents an angle formed by the axis AM with respect to the solid line BM. This angle α is an angle formed by the protrusion 34 with respect to the reference surface 36 of the lug bottom 18. The height HM, the interval WM, and the angle α are measured in a state where no load is applied.

  In the tire 2, the height HM of the protrusion 34 is preferably 6 mm or more and 10 mm or less. By setting the height HM to be 6 mm or more, the protrusions 34 can effectively contribute to the reduction of mud adhesion. From this viewpoint, the height HM is more preferably 8 mm or more. By setting the height HM to 10 mm or less, the tire 2 including the lug bottom 18 having a large number of protrusions 34 can be manufactured stably. From this viewpoint, the height HM is more preferably 9 mm or less.

  In the tire 2, the interval WM between the protrusions 34 is 1.5 mm or more and less than 3.0 mm. By setting the interval WM to be less than 3.0 mm, the protrusions 34 can be disposed on the lug bottom 18 with high density. In the tire 2, adhesion of mud can be reduced not only in uncultivated land but also in already cultivated land. In this respect, the interval WM is more preferably 2.0 mm or less. By setting the interval WM to be 1.5 mm or more, the tire 2 including the lug bottom 18 having a large number of protrusions 34 can be manufactured stably. The distance WM is particularly preferably set to 1.5 mm from the viewpoint that the tire 2 is stably manufactured and adhesion of mud is effectively reduced.

  In the tire 2, the angle α formed by the protrusion 34 with respect to the reference surface 36 of the lug bottom 18 is preferably 80 ° or more and 90 ° or less. By setting the angle α to 80 ° or more, the tire 2 including the lug bottom 18 having a large number of protrusions 34 can be manufactured stably. By setting the angle α to 90 ° or less, the protrusions 34 can effectively contribute to the reduction of mud adhesion. From the viewpoint of stably manufacturing the tire 2 and effectively reducing adhesion of mud, it is particularly preferable that the angle α is 90 °.

In the tire 2, the cross-sectional area of the protrusion 34 is preferably 0.8 mm ² or more and 7.1 mm ² or less. By setting the cross-sectional area to 0.8 mm ² or more, the protrusions 34 can effectively reduce mud adhesion. By setting the cross-sectional area to 7.1 mm ² or less, the protrusions 34 can be disposed on the lug bottom 18 with high density. The protrusions 34 can effectively contribute to the reduction of mud adhesion. From this viewpoint, the cross-sectional area is more preferably 3.2 mm ² or less. In the tire 2, since the main body 38 of the protrusion 34 has a cylindrical shape, the outer diameter of the main body 38 is preferably 1 mm or more, and more preferably 3 mm or less.

  As described above, in the tire 2, the large number of sub-projections 42 constituting the sub-projection group 32 are lower than the projections 34. Each sub-projection 42 is configured such that its height gradually decreases from the projection group 30 side toward the outside. The sub-projection group 32 can reduce the amount of mud adhering to the base of the projection 34 disposed on the outer portion of the projection group 30. In the tire 2, adhesion of mud is further effectively suppressed.

  In FIG. 5, a double-headed arrow WB represents the distance between the protrusion 34 and the auxiliary protrusion 42 a closest to the protrusion 34. A double-headed arrow WS represents the distance between the sub-projection 42a and another sub-projection 42b closest to the sub-projection 42a. A solid line BM represents the reference surface 36 of the lug bottom 18. The solid line SL is a straight line extending while abutting on the tip portion of the projection 34 closest to the sub-projection group 32 and the tip portion of the sub-projection 42 b located on the outer portion of the sub-projection group 32. The solid line SL is inclined with respect to the solid line BM. An angle β represents an inclination angle formed by the solid line SL with respect to the solid line BM. The interval WB, the interval WS, and the angle β are measured in a state where no load is applied.

  In the tire 2, the interval WB is preferably less than 3.0 mm and more preferably 2.0 mm or less from the viewpoint that adhesion of mud can be effectively reduced. This interval WB is preferably 1.5 mm or more. From the same viewpoint, the interval WS is preferably less than 3.0 mm, and more preferably 2.0 mm or less. This interval WS is preferably 1.5 mm or more.

  In the tire 2, the angle β is preferably 120 ° or more, and preferably 140 ° or less from the viewpoint that adhesion of mud can be effectively reduced.

  In the tire 2, the hardness of the crosslinked rubber constituting the protrusion 34 is preferably 50 or more and 90 or less. The protrusion 34 whose hardness is set to 50 or more has high rigidity. The projection 34 can effectively reduce mud adhesion due to its restoring force. In this respect, the hardness is more preferably 52 or higher, and particularly preferably 55 or higher. By setting the hardness to 90 or less, the rigidity of the protrusion 34 can be appropriately maintained. The projection 34 can effectively reduce mud adhesion due to its restoring force. In this respect, the hardness is more preferably 88 or less, and particularly preferably 85 or less.

  In the present invention, the hardness is measured by a type A durometer according to JIS-K6253. For this measurement, a test piece formed by crosslinking the rubber composition constituting the protrusion 34 is used. This test piece is obtained by holding the rubber composition in a mold having a temperature of 160 ° C. for 10 minutes. This hardness is measured under conditions where the temperature is 25 ° C.

  In the tire 2, the hardness of the crosslinked rubber constituting the sub-projections 42 is preferably 50 or greater and 90 or less. The sub-projections 42 whose hardness is set to 50 or more have high rigidity. The sub-projections 42 can effectively contribute to the reduction of mud adhesion. In this respect, the hardness is more preferably 52 or higher, and particularly preferably 55 or higher. By setting the hardness to 90 or less, the rigidity of the sub-projection 42 can be appropriately maintained. The sub-projections 42 can effectively contribute to the reduction of mud adhesion. In this respect, the hardness is more preferably 88 or less, and particularly preferably 85 or less.

  In the tire 2, the lug bottom 18 is formed by crosslinking a rubber composition equivalent to the main body 14 of the tread 4. The manufacturing method of the tire 2 does not require a special process for forming the lug bottom 18. In the tire 2, an increase in production cost is suppressed.

  In the present invention, the size and angle of each member of the tire 2 are measured in a state where the tire 2 is incorporated in a regular rim and the tire 2 is filled with air so as to have a regular internal pressure. At the time of measurement, no load is applied to the tire 2. In the present specification, the normal rim means a rim defined in a standard on which the tire 2 depends. “Standard rim” in the JATMA standard, “Design Rim” in the TRA standard, and “Measuring Rim” in the ETRTO standard are regular rims. In the present specification, the normal internal pressure means an internal pressure defined in a standard on which the tire 2 relies. “Maximum air pressure” in JATMA standard, “maximum value” published in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” in TRA standard, and “INFLATION PRESSURE” in ETRTO standard are normal internal pressures.

  Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be construed in a limited manner based on the description of the examples.

[Example 1]
A tire with lugs of Example 1 having the basic configuration shown in FIGS. 1 and 2 and having the specifications shown in Table 1 below was obtained. The tire size is 13.6-26-4PR. The lug bottom of the tire includes a projection group and a sub projection group located around the projection group. A projection group consists of many projections. The sub projection group is composed of a large number of sub projections. The cross-sectional area of each protrusion was 2.3 mm ² . The main body of the protrusion was cylindrical, and the outer diameter of the main body was 1.7 mm. An angle α formed by the main axis AM of the protrusion with respect to the reference surface BM of the lug bottom was 90 °. The protrusion interval WM was set to 1.8 mm. The height HM of the protrusion was 10 mm. A large number of sub-projections constituting the sub-projection group were arranged in two rows outside the projection group. An angle β formed by a straight line SL extending in contact with each tip portion from the sub-projection located on the outer portion of the sub-projection group with respect to the projection group is made 140 ° with respect to the reference surface BM of the lug bottom. It was. The hardness of the crosslinked rubber constituting the lug bottom was 59.

[Example 2]
A lug-equipped tire was obtained in the same manner as in Example 1 except that the height HM of the protrusions was as shown in Table 1 below.

[Comparative Example 2]
A lug-equipped tire was obtained in the same manner as in Example 1 except that the height HM of the protrusions and the interval WM of the protrusions were as shown in Table 1 without providing the auxiliary protrusions.

[Comparative Example 1]
A lug-equipped tire was obtained in the same manner as in Example 1 except that no protrusions and sub-projections were provided on the lug bottom.

[Examples 3 to 9]
A lug-equipped tire was obtained in the same manner as in Example 1 except that the sub-projections were not provided on the lug bottom, and the projection spacing WM and projection height HM were as shown in Tables 1 and 2 below.

[Evaluation of adhesion of mud in already cultivated land]
A prototype tire was mounted on an agricultural tractor (38 hp). The rim was 26 × W11 and the tire air pressure was 100 kPa. A running test was conducted in a wetland where the amount of footprint settlement was about 25 cm. The wetland mud was clayey. With this tractor, the wet field (cultivated land) immediately after tillage was run straight while rotary tilling, and the adhesion of mud on the tilled land was evaluated. The evaluation results are shown in Tables 1 and 2 as index values in which the mud adhesion amount of Comparative Example 1 is 100. It shows that adhesion of mud is suppressed, so that this figure is small.

[Evaluation of adhesion of mud in uncultivated land]
A prototype tire was mounted on an agricultural tractor (38 hp). The rim was 26 × W11 and the tire air pressure was 100 kPa. The paddy field before plowing (uncultivated land) was run straight while rotary plowing with a tractor, and the adhesion of mud on the uncultivated land was evaluated. The evaluation results are shown in Tables 1 and 2 as index values in which the mud adhesion amount of Comparative Example 1 is 100. It shows that adhesion of mud is suppressed, so that this figure is small.

  As shown in Table 1 and Table 2, in the tire with a lug of the example, adhesion of mud is effectively suppressed. From this evaluation result, the superiority of the present invention is clear.

  The traveling body with a lug according to the present invention can be mounted on various agricultural machines and light civil engineering construction machines.

2 ... tire 4 ... tread 6 ... sidewall 8 ... bead 10 ... carcass 12 ... belt 14 ... main body 16 ... lug 18 ... lug bottom 30 ...・ Protrusion group 32 ... Sub-projection group 34 ... Protrusion 36 ... Reference plane 42 ... Sub-projection

Claims (7)

A tread having a main body, a plurality of lugs protruding from the main body, and a lug bottom;
This lug bottom has a group of protrusions,
This projection group consists of a number of projections protruding from the reference surface of the lug bottom,
These protrusions are arranged at intervals,
A traveling body with a lug in which the distance is 1.5 mm or more and 1.8 mm or less . The traveling body with a lug according to claim 1, wherein a height of the protrusion is 6 mm or more and 10 mm or less. The traveling body with a lug according to claim 1 or 2 , wherein an angle formed by the protrusion with respect to the reference plane is 80 ° or more and 90 ° or less. The traveling body with a lug according to any one of claims 1 to 3 , wherein a cross-sectional area of the protrusion is 0.8 mm ² or more and 7.1 mm ² or less. The protrusion is cylindrical,
The running body with a lug according to any one of claims 1 to 4 , wherein an outer diameter of the protrusion is 1 mm or more and 3 mm or less. The lug bottom further comprises a sub-projection group outside the projection group;
This sub-projection group consists of a large number of sub-projections protruding from the reference surface of the lug bottom,
The traveling body with a lug according to any one of claims 1 to 5 , wherein a height of each sub-projection is lower than a height of the projection. The height of the sub-projection located on the side of the projection group is lower than the height of the projection,
The traveling body with a lug according to claim 6 , wherein the height of the other sub-projections positioned outside the sub-projections is lower than the height of the sub-projections.

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