JP2015217723A - Travel body with lug - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a travel body with lug excellent in deposition reduction effect of a mud.SOLUTION: A tread 22 of a travel body 20 with lug comprises: plural lugs 34 projecting toward an outside direction; and plural lug bottoms 36. Each of the lug bottoms 36 is disposed between the lugs 34 adjacent in a rotation direction. The lug bottom 36 comprises: plural projections 42 projecting a reference surface BM to the outside; and plural walls 44 projecting from the reference surface BM to outside direction, and bridged between the adjacent projections 42. A gap of the adjacent projections 42 is 1.5 mm or more and less than 3.0 mm. Preferably, a ratio of the height HW of the wall 44 to height of the projection (HW/HN) is 0.20 or more and 0.60 or less.

Description

  The present invention relates to a traveling body with a lug. In detail, this invention relates to the traveling body with a lug which can be mounted | worn with the agricultural machine and light civil engineering construction machine which drive | work a wet field, a soft ground, etc.

  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 is provided with a number of lugs protruding outward in the radial direction. 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.

  Various investigations have been made on reducing the adhesion of mud to a traveling body with a lug. An example of this study is disclosed in Japanese Unexamined Patent Application Publication Nos. 2007-161192 and 2011-73656. FIG. 8 shows a part of a cross section of the traveling body 2 disclosed in these publications. In this figure, the lug 4 and the lug bottom 6 are shown. As shown in the figure, in the traveling body 2, a large number of protrusions 8 are arranged on the lug bottom 6. FIG. 9 shows a schematic diagram in which the lug bottom 6 is enlarged. The lug bottom 6 is in contact with the ground 10. At this time, the protrusion 8 is pressed by the ground 10 and deforms so as to fall down. The tip portion of the protrusion 8 abuts on the side surface of another protrusion 8 adjacent to the protrusion 8. By this contact, a space is formed between the ground 10 and the reference surface 12 of the lug bottom 6. Thereby, adhesion of mud to the lug bottom 6 is reduced. When the traveling body 2 rotates and the lug bottom 6 is not grounded, the deformed protrusion 8 is restored. By this restoration, mud adhering to the lug bottom 6 is removed. The projection 8 effectively prevents mud from adhering to the lug bottom 6.

JP 2007-161192 A JP 2011-73656 A

  The working machine equipped with the lug traveling body repeats not only straight traveling but also turning. When turning, a larger load is applied to the traveling body from various directions than when traveling straight. This increases the deformation of the protrusion. FIG. 10 shows this state. When the deformation of the protrusion 8 increases, the space between the ground 10 and the reference surface 12 of the lug bottom 6 decreases. This reduces the mud adhesion preventing effect of the protrusion 8. Furthermore, when mud strongly adheres to the lug bottom 6 due to a large load, the deformed protrusion 8 may not be restored even after the lug bottom 6 is not grounded. The mud cannot be removed by the restoration of the protrusions 8. In the traveling body 2 described in JP 2007-161192 A and JP 2011-73656 A, mud adhesion may not be prevented.

  When the traveling body with a lug travels, the protrusion repeats deformation and restoration. Further, as described above, this protrusion may be greatly deformed. Furthermore, the traveling body may step on a hard foreign object such as a stone or a piece of wood. As a result, it has been confirmed that the protrusion 8 described in JP2007-161192A and JP2011-73656A is cut. When the protrusions 8 to be cut increase, the effect of preventing mud adhesion is significantly reduced. It is important to prevent the protrusions from being cut.

  In a field that contains a lot of moisture, the moisture adheres to the surface of the tire. The adhering moisture remains on the tire surface due to surface tension. Moisture remaining at the bottom of the rug suppresses adhesion of mud to the rug bottom. The protrusions 8 of JP 2007-161192 A and JP 2011-73656 A have an effect of increasing the amount of moisture remaining on the lug bottom 6. In order to further improve the effect of preventing the mud from adhering to the lug bottom 6, it is effective to further increase the amount of moisture remaining on the lug bottom 6.

  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 whose outer surface forms a tread surface. The tread includes a plurality of lugs protruding outward and a plurality of lug bottoms. Each lug bottom is located between adjacent lugs in the rotational direction. The lug bottom includes a large number of protrusions protruding outward from the reference surface, and a large number of walls protruding outward from the reference surface and bridged between the adjacent protrusions. The interval between the adjacent protrusions is 1.5 mm or more and less than 3.0 mm.

  Preferably, the ratio (HW / HM) of the wall height HW to the projection height HM is 0.20 or more and 0.60 or less.

  Preferably, a ratio (TW / DM) of the wall thickness TW to the width DM of the protrusion is 0.30 or more and 1.0 or less.

  Preferably, the interval between the protrusions is 2.0 mm or less.

  Preferably, the height of the protrusion is 6 mm or more and 10 mm or less.

  Preferably, an angle formed by the protrusion with respect to the reference plane is not less than 80 ° and not more than 90 °.

Preferably, the cross-sectional area of the protrusion is 0.8 mm ² or more and 7.1 mm ² or less.

  Preferably, the protrusion has a cylindrical shape, and the outer diameter of the protrusion is not less than 1 mm and not more than 3 mm.

  In the traveling body with a lug according to the present invention, the lug bottom includes a large number of protrusions protruding from the reference surface, and a large number of walls extending between the protrusions protruding from the reference surface and adjacent to each other. . This wall improves the rigidity of the protrusion. This wall prevents the protrusions from being excessively deformed when a large load during turning is applied to the traveling body with a lug. Thereby, the space between the ground and the lug bottom is secured. In this traveling body with a lug, even when turning, a high effect of preventing adhesion of mud is maintained. The protrusion having improved rigidity is excellent in restoring force after being deformed. Even if mud is strongly attached to the bottom of the lug, this protrusion can be restored. This restoration can remove the mud. Further, the protrusion having improved rigidity is prevented from being cut. In addition, this wall increases the surface area of the lug bottom. This allows more moisture to stay at the bottom of the rug. In this traveling body with a lug, adhesion of mud to the lug bottom is effectively prevented.

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 an enlarged view showing a part of the lug bottom of FIG. 1. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 is an enlarged cross-sectional view showing the protrusions and walls of FIG. FIG. 6 is a schematic diagram showing a state where the lug bottom is in contact with the ground. FIG. 7 is a schematic diagram showing a state in which a large load is applied to the lug bottom of FIG. 6. FIG. 8 is a cross-sectional view showing a part of a lug and a lug bottom of a conventional traveling body with a lug. FIG. 9 is a schematic diagram showing a state where the lug bottom of FIG. 8 is in contact with the ground. FIG. 10 is a schematic diagram showing a state in which a large load is applied to the lug bottom of FIG. 9.

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

  FIG. 1 is a development view showing a part of a tire 20 with lugs as a running body with lugs according to the present invention. In FIG. 1, the left-right direction is the axial direction of the tire 20. The direction indicated by the arrow A is the rotation direction of the tire 20. FIG. 2 is a cross-sectional view taken along line II-II in FIG. In FIG. 2, the vertical direction is the radial direction of the tire 20, and the horizontal direction is the axial direction of the tire 20. The lug-equipped tire 20 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 20 may be mounted on a light civil engineering construction machine such as a trencher and a dozer.

  The tire 20 includes a tread 22, a sidewall 24, a bead 26, a carcass 28, and a belt 30. Although not shown, the tire 20 includes a tube. This tube is filled with air.

  The tread 22 has a shape protruding outward in the radial direction. The tread 22 forms a tread surface 32 that contacts the ground. The tread 22 is made of a crosslinked rubber. The tread 22 includes a plurality of lugs 34 and a plurality of lug bottoms 36.

  The plurality of lugs 34 are alternately arranged on the left and right in the rotation direction. Each lug 34 protrudes radially outward. The lug 34 extends rearward in the rotational direction from the vicinity of the center of the tread 22 toward the end of the tread 22. This lug 34 sinks into the mud constituting the farm field and scratches this mud. The lug 34 can contribute to the traction of the tire 20. The shape, interval, height, and the like of the lugs 34 are appropriately determined in consideration of the specifications of the tire 20 and the like.

  The plurality of lug bottoms 36 are alternately arranged on the left and right in the rotation direction. As shown in FIG. 1, each lug bottom 36 is located between adjacent lugs 34 in the rotational direction. In the tire 20, the plurality of lugs 34 and the plurality of lug bottoms 36 are alternately arranged in the rotation direction. The number of lugs 34 provided on the tread 22 is equal to the number of lug bottoms 36.

  The sidewall 24 extends substantially inward in the radial direction from the end of the tread 22. The sidewall 24 is made of a crosslinked rubber. The sidewall 24 absorbs an impact from the road surface by bending. Further, the sidewall 24 prevents the carcass 28 from being damaged.

  The bead 26 is located substantially inward of the sidewall 24 in the radial direction. The bead 26 includes a core 38 and an apex 40 that extends radially outward from the core 38. The core 38 has a ring shape. The core 38 includes a wound non-stretchable wire. A typical material for the wire is steel. The apex 40 is tapered outward in the radial direction. The apex 40 is made of a highly hard crosslinked rubber. In addition, this bead 26 may be composed of only the core 38. In this case, the bead 26 does not include the apex 40.

  The carcass 28 includes a first ply 28a and a second ply 28b. The first ply 28 a and the second ply 28 b are spanned between the beads 26 on both sides, and extend along the inside of the tread 22 and the sidewall 24. The first ply 28a and the second ply 28b are folded around the core 38 from the inner side to the outer side in the axial direction.

  Although not shown, the first ply 28a and the second ply 28b 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 28 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 30 is located on the radially outer side of the carcass 28. The belt 30 is laminated with the carcass 28. The belt 30 reinforces the carcass 28. The tire 20 may not be provided with the belt 30.

  Although not shown, the belt 30 includes a large number 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 an enlarged view showing a part of the lug bottom 36 of FIG. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 4 shows a lug bottom 36 between the lug 34a and another lug 34b located on the rear side in the rotational direction of the lug 34a. As shown in FIGS. 3 and 4, the lug bottom 36 includes a number of protrusions 42 and a number of walls 44. FIG. 5 is an enlarged view of the protrusion 42 and the wall 44 of FIG.

  As shown in FIG. 3, these protrusions 42 are two-dimensionally arranged in the rotation direction A and the axial direction of the tire 20. In the tire 20, the interval between the protrusions 42 adjacent in the rotation direction is equal to the interval between the protrusions 42 adjacent in the axial direction. A double arrow WM is an interval between the adjacent protrusions 42. In the tire 20, the interval WM is 1.5 mm or more and less than 3.0 mm. The interval between the protrusions 42 in the rotation direction may be different from the interval between the protrusions 42 in the axial direction. In this case, each interval is 1.5 mm or more and less than 3.0 mm.

  In FIG. 5, a two-dot chain line BM represents a reference plane of the lug bottom 36. The protrusion 42 protrudes outward in the radial direction from the reference surface BM of the lug bottom 36. These protrusions 42 have the same height. Each protrusion 42 is cylindrical. The cross-sectional shape of the protrusion 42 is a circle. The tip portion of the protrusion 42 is rounded.

  As shown in FIG. 3, the wall 44 spans between the adjacent protrusions 42. As shown in FIGS. 4 and 5, the wall 44 protrudes substantially outward in the radial direction from the reference surface BM of the lug bottom 36. Each wall 44 is plate-shaped. These walls 44 have the same height.

  Below, the effect of this invention is demonstrated.

  A large load is applied to the traveling body with a lug during turning. At this time, in the traveling body with a lug in which a large number of protrusions are provided on the lug bottom so far, the deformation of the protrusion becomes large and the space between the ground and the reference surface of the lug bottom becomes small. This reduces the mud adhesion prevention effect of the protrusions.

  In the tire with a lug 20 according to the present invention, the lug bottom 36 has a large number of protrusions 42 protruding from the reference surface BM and a large number of protrusions 42 protruding from the reference surface BM and bridged between the adjacent protrusions 42 and the protrusions 42. Wall 44. FIG. 6 is a schematic diagram showing a state where the tire 20 according to the present invention is in contact with the ground 46. What is indicated by an arrow A is the rotational direction of the tire 20. The tire 20 in use receives a load in the direction indicated by the arrow B. For this reason, the protrusion 42 falls to the rear side in the rotation direction. The tip portion of the protrusion 42 abuts on the side surface of another protrusion 42 adjacent to the protrusion 42. By this contact, a space is formed between the ground 46 and the reference surface BM of the lug bottom 36. FIG. 7 shows a state in which a larger load is applied to the tire 20 during turning. In the tire 20, the wall 44 supports the protrusion 42. This wall 44 improves the rigidity of the protrusion 42. The wall 44 prevents the protrusion 42 from being excessively deformed when a large load is applied to the traveling body with the lug 34. Thereby, a space is secured between the ground 46 and the reference plane BM of the lug bottom 36. In the tire 20, a high mud adhesion preventing effect is maintained.

  In a conventional traveling body with a lug, if mud is strongly attached to the lug bottom due to a large load, the deformed protrusion may not be restored even after the lug bottom stops contacting the ground. This is because the force that mud adheres to the bottom of the lug is greater than the restoring force of the protrusion. This makes it impossible to remove the mud by restoring the protrusions.

  As described above, the wall 44 spanned between the protrusions 42 improves the rigidity of the protrusions 42. The protrusion 42 having improved rigidity is excellent in restoring force after being deformed. Even if mud is strongly attached to the lug bottom 36, the protrusion 42 can be restored. The mud can be removed by restoring the protrusions 42.

  When the traveling body with a lug travels, the protrusion repeats deformation and restoration. In addition, this protrusion may be greatly deformed. Furthermore, the traveling body may step on a hard foreign object such as a stone or a piece of wood. Accordingly, it has been confirmed that the cutting of the protrusion occurs in the conventional traveling body with a lug. When the number of protrusions to be cut increases, the effect of preventing mud adhesion is significantly reduced. It is important to prevent the protrusions from being cut.

  In the lug-equipped tire 20 according to the present invention, since the rigidity of the protrusion 42 is improved by the wall 44, the protrusion 42 is prevented from being cut. In the tire 20, the reduction of the mud adhesion preventing effect due to the cutting of the protrusions 42 is prevented.

  Moisture adhering to the surface of the traveling body remains on the surface due to surface tension. Moisture remaining at the bottom of the rug suppresses adhesion of mud to the rug bottom. In order to further improve the effect of preventing the mud from adhering to the bottom of the rug, it is effective to increase the amount of water remaining at the bottom of the rug.

  In the tire with lugs 20 according to the present invention, the wall 44 spanned between the protrusions 42 increases the surface area of the lug bottom 36. As a result, more water can remain at the lug bottom 36 than in the conventional traveling body with lugs. In the tire with lugs 20, adhesion of mud to the lug bottom 36 is effectively prevented.

  In the tire 20, mud adherence is suppressed, so the lug 34 keeps scraping the mud stably. In the tire 20, excellent traction is maintained. In the tire 20, 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 by the mud on the paved road is effectively prevented. In the tire 20, since the position where the mud is separated from the tire 20 is low, damage of the seedlings and the like that have just been planted by the falling mud is prevented.

  As described above, in the tire 20, the interval WM between the protrusions 42 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 42 can be disposed on the lug bottom 36 with high density. In the tire 20, adhesion of mud can be reduced. 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 20 including the lug bottom 36 having a large number of protrusions 42 can be manufactured stably. The distance WM is particularly preferably set to 1.5 mm from the viewpoint that the tire 20 is stably manufactured and adhesion of mud is effectively reduced.

  In FIG. 5, the double arrow HM is the height of the protrusion 42. Specifically, it is the distance from the reference surface BM to the tip of the protrusion 42 in the direction perpendicular to the reference surface BM. The double arrow HW is the height of the wall 44. Specifically, it is the distance from the reference surface BM to the outer end of the wall 44 in the direction perpendicular to the reference surface BM. The height HM and the height HW are measured in a state where no load is applied.

  The ratio (HW / HM) of the height HW of the wall 44 to the height HM of the protrusion 42 is preferably 0.2 or more. By setting the ratio (HW / HM) to 0.2 or more, the wall 44 effectively contributes to the improvement of the rigidity of the protrusion 42. The protrusion 42 is prevented from being greatly deformed. In the tire 20, even when a large load is applied to the tire 20 during turning, a space is secured between the ground 46 and the reference surface BM of the lug bottom 36. This wall 44 contributes effectively to the improvement of the restoring force of the protrusion 42. Even if the mud strongly adheres to the lug bottom 36, the mud can be removed by restoring the protrusions 42. Further, the protrusion 42 is effectively prevented from being cut. In the lug-equipped tire 20, the mud adherence prevention effect is prevented from being reduced by cutting the protrusions 42. In the tire 20 with a lug, the effect of preventing adhesion of mud to the lug bottom 36 is further improved. In this respect, the ratio (HW / HM) is more preferably equal to or greater than 0.3.

  The ratio (HW / HM) is preferably 0.6 or less. By setting the ratio (HW / HM) to 0.6 or less, the deformed protrusion 42 can effectively cover the reference surface BM of the lug bottom 36. In the tire 20, a space is secured between the ground 46 and the reference surface BM of the lug bottom 36. In the tire with lugs 20, adhesion of mud to the lug bottom 36 is effectively prevented.

  In FIG. 3, the double arrow TW is the thickness of the wall 44. Specifically, it is the distance between the two side surfaces of the wall 44 measured along a line perpendicular to the side surface of the wall 44. A double arrow DM is the width of the protrusion 42. In the tire 20, the protrusion 42 is a cylinder, and the width DM is the outer diameter of the cylinder. The thickness TM and the width DM are measured in a state where no load is applied.

  The ratio (TW / DM) of the thickness TW of the wall 44 to the width DM of the protrusion 42 is preferably 0.3 or more. By setting the ratio (TW / DM) to 0.3 or more, the wall 44 effectively contributes to the improvement of the rigidity of the protrusion 42. The protrusion 42 is prevented from being greatly deformed. In the tire 20, even when a large load is applied to the tire 20 during turning, a space is secured between the ground 46 and the reference surface BM of the lug bottom 36. This wall 44 contributes effectively to the improvement of the restoring force of the protrusion 42. Even if the mud strongly adheres to the lug bottom 36, the mud can be removed by restoring the protrusions 42. Further, the protrusion 42 is effectively prevented from being cut. In the lug-equipped tire 20, the mud adherence prevention effect is prevented from being reduced by cutting the protrusions 42. In the tire 20 with a lug, the effect of preventing adhesion of mud to the lug bottom 36 is further improved. In this respect, the ratio (TW / DM) is more preferably equal to or greater than 0.7.

  The ratio (TW / DM) is preferably 1.0 or less. By setting the ratio (TW / DM) to 1.0 or less, the protrusions 42 can be disposed on the lug bottom 36 with high density. The protrusions 42 can effectively contribute to the reduction of mud adhesion.

  In the tire 20, the height HM of the protrusion 42 is preferably 6 mm or greater and 10 mm or less. By setting the height HM to be 6 mm or more, the protrusions 42 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 20 including the lug bottom 36 having a large number of protrusions 42 can be manufactured stably. From this viewpoint, the height HM is more preferably 9 mm or less.

  In FIG. 5, the alternate long and short dash line AM represents the axis of the protrusion 42. The angle α represents an angle formed by the axis AM with respect to the reference plane BM. This angle α is an angle formed by the protrusion 42 with respect to the reference plane BM of the lug bottom 36. The angle α is measured in a state where no load is applied.

  In the tire 20, the angle α formed by the protrusion 42 with respect to the reference surface BM of the lug bottom 36 is preferably 80 ° or more and 90 ° or less. By setting the angle α to 80 ° or more, the tire 20 including the lug bottom 36 having a large number of protrusions 42 can be manufactured stably. By setting the angle α to 90 ° or less, the protrusions 42 can effectively contribute to the reduction of mud adhesion. From the viewpoint of stably manufacturing the tire 20 and effectively reducing the adhesion of mud, it is particularly preferable that the angle α is 90 °.

In the tire 20, the cross-sectional area of the protrusion 42 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 42 can effectively reduce mud adhesion. By setting the cross-sectional area to 7.1 mm ² or less, the protrusions 42 can be disposed on the lug bottom 36 with high density. The protrusions 42 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 this tire 20, since the protrusion 42 is cylindrical, the outer diameter of the protrusion 42 is preferably 1 mm or more, and preferably 3 mm or less.

  In the tire 20, the hardness of the crosslinked rubber constituting the protrusion 42 and the wall 44 is preferably 50 or greater and 90 or less. The protrusion 42 and the wall 44 whose hardness is set to 50 or more have high rigidity. The protrusion 42 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 42 can be appropriately maintained. The protrusion 42 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 42 and the wall 44 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 present invention, the size and angle of each member of the tire 20 are measured in a state where the tire 20 is incorporated in a regular rim and the tire 20 is filled with air so as to have a regular internal pressure. During the measurement, no load is applied to the tire 20. In the present specification, the normal rim means a rim defined in a standard on which the tire 20 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 20 depends. “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 configuration shown in FIGS. 1 and 2 was obtained. The size of this tire is 13.6-26-4PR. The lug bottom of the tire includes a number of protrusions and a number of walls having the specifications shown in Table 1. This protrusion is cylindrical. As shown in Table 1, since the width of the protrusion is 1.7 mm, the sectional area of each protrusion is 2.3 mm ² . 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 °.

[Comparative Example 1]
A lug-equipped tire was obtained in the same manner as in Example 1 except that no wall was provided. This is a conventional lug tire having a lug bottom projection.

[Comparative Example 2]
A lug-equipped tire of Comparative Example 2 was obtained in the same manner as in Example 1 except that no wall was provided and the protrusion interval WM was as shown in Table 1.

[Example 2-9]
The lugs of Example 2-9 were the same as Example 1 except that the wall height HW and thickness TW were changed and the ratio (HW / HM) and ratio (TW / DM) were changed as shown in Table 2-3. An attached tire was obtained.

[Evaluation of adhesion of mud]
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 and turned while rotary plowing with a tractor, and the adhesion of mud was evaluated. This evaluation result is shown in Table 1-3 as an index value in which the mud adhesion amount of Comparative Example 1 is 100. The smaller this value is, the less mud adheres. The smaller this value, the better.

  As shown in Table 1-3, adhesion of mud is effectively suppressed in the tire with a lug of the example. 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 ... traveling body 4, 34 ... lug 6, 36 ... lug bottom 8, 42 ... projection 10, 46 ... ground 12 ... reference plane 20 ... tire 22 ... Tread 24 ... sidewall 26 ... bead 28 ... carcass 28a ... first ply 28b ... second ply 30 ... belt 32 ... tread surface 38 ... core 40 ...・ Apex 44 ・ ・ ・ Wall

Claims (8)

It has a tread whose outer surface forms a tread surface,
The tread includes a plurality of lugs protruding outward and a plurality of lug bottoms,
Each lug bottom is located between adjacent lugs in the direction of rotation,
The lug bottom includes a large number of protrusions protruding outward from the reference surface, and a large number of walls protruding outward from the reference surface and bridged between adjacent protrusions,
A traveling body with a lug in which an interval between adjacent protrusions is 1.5 mm or more and less than 3.0 mm.   The travel body with a lug according to claim 1, wherein a ratio (HW / HM) of the height HW of the wall to the height HM of the protrusion is 0.20 or more and 0.60 or less.   The travel body with a lug according to claim 1 or 2, wherein a ratio (TW / DM) of a thickness TW of the wall to a width DM of the protrusion is 0.30 or more and 1.0 or less.   The travel body with a lug according to any one of claims 1 to 3, wherein an interval between the protrusions is 2.0 mm or less.   The traveling body with a lug according to any one of claims 1 to 4, wherein a height of the protrusion is 6 mm or more and 10 mm or less.   The traveling body with a lug according to any one of claims 1 to 5, wherein an angle formed by the protrusion with respect to the reference surface is 80 ° or more and 90 ° or less. The traveling body with a lug according to any one of claims 1 to 6, 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 7, wherein an outer diameter of the protrusion is 1 mm or more and 3 mm or less.

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