JP2018176891A - Crawler - Google Patents

Abstract

To provide a crawler 2 whose durability has been improved. SOLUTION: This crawler 2 has a belt 10 with which a sprocket 6 abuts from the inside, a large number of drive holes 18 with which teeth 8 of the sprocket 6 are engaged respectively, and an elastic valve located inside each drive hole 18 It has 20 and. The drive hole 18 includes a pair of transverse edges 22 extending in the width direction and a pair of longitudinal edges 24 extending in the longitudinal direction. The resilient valve 20 comprises at least two plates 26. Each plate 26 extends inward from the longitudinal edge 24 in the width direction. The plate 26 is separated from the lateral edge 22. [Selected figure] Figure 3

Description

  The present invention relates to a crawler. In particular, the present invention relates to crawlers for traveling devices such as agricultural machines, construction machines and the like.

  Crawler-type traveling devices are used in agricultural machines such as combine harvesters and construction machines such as backhoes. This traveling device has an elastic crawler (hereinafter, also simply referred to as a crawler).

  The crawler is in the form of an endless belt. The crawler comprises a belt forming a loop and a number of lugs. The lugs are spaced along the length of the belt. The lugs project outwardly from the belt.

  The traveling device is provided with a sprocket. The periphery of this sprocket is provided with a number of teeth. These teeth are arranged along the periphery.

  The crawler is provided with holes. The teeth of the sprockets bite into this hole. In the traveling device, when the sprocket rotates, the teeth engaged in the holes drive the crawler. The traveling device is thereby moved.

  The traveling device usually travels on a road surface composed of soil, gravel, etc. (hereinafter simply referred to as soil). Soil adheres to the crawler.

  The crawler is configured by covering a metal component such as a core metal or a tensile body with a crosslinked rubber. If soil bites between the coating and the sprocket or between the coating and the rolling wheel, the coating may be damaged. Depending on the degree of damage to the coating material, there is a concern that the internal parts may be rusted and the entire crawler may be damaged. For these reasons, various studies have been conducted on crawlers in order to improve the durability of the crawlers. Examples of this study are shown in Patent Documents 1 and 2 below.

JP 2003-175868 gazette JP, 2009-107442, A

  In the crawler disclosed in Patent Document 1 mentioned above, a thin film is provided which covers the entire hole. This membrane prevents the infiltration of soil from the holes into the inner part of the crawler.

  Soil also penetrates the inside of the crawler from the side of the crawler. The aforementioned membranes close the pores. In this crawler, the soil which has invaded from the side stagnates because the soil is not discharged through the holes.

  In this crawler, although the amount of soil invading into the inside could be reduced by closing the hole with a membrane, there is a circumstance that the occurrence of damage due to the biting of the soil can not be sufficiently prevented. Furthermore, since the film is thin, there is a possibility that the film may be deteriorated and the film itself may be broken by use. The same applies to the crawler disclosed in Patent Document 2 above. In order to improve the durability, it is required to establish a technology that does not prevent the soil from being discharged from the inside while suppressing the intrusion of the soil into the inside of the crawler.

  An object of the present invention is to provide a crawler with improved durability.

  The crawler according to the present invention includes a belt with which a sprocket abuts from the inside, a number of drive holes in which the teeth of the sprockets engage respectively, and an elastic valve located inside each drive hole. The drive hole includes a pair of transverse edges extending in the width direction and a pair of longitudinal edges extending in the longitudinal direction. The resilient valve comprises at least two plates. Each plate extends inwardly from the longitudinal edge in the width direction. The plate is separated from the lateral edge.

  Preferably, in this crawler, the resilient valve comprises at least two of the plates extending inwardly from one of the longitudinal edges. These plates are juxtaposed in the longitudinal direction.

  Preferably, in the crawler, in the cross section of the belt, the plate has a tapered shape from the root to the tip.

  Preferably, in this crawler, the plate has an inner surface located on the inner side and an outer surface located on the outer side. The inclination of the inner surface to the width direction is larger than the inclination of the outer surface to the width direction.

  Preferably, in the crawler, in the cross section of the belt, the contour of the outer surface and the contour of the inner surface are represented by straight lines.

  Preferably, in the crawler, the contour of the outer surface is represented by a straight line in the cross section of the belt. The contour of the inner surface comprises an arc, which extends from the root of the plate towards the tip.

  Preferably, in the crawler, the contour of the outer surface is represented by a straight line in the cross section of the belt. The plate is configured such that its thickness gradually decreases from the root to the tip of the plate.

  In the crawler according to the present invention, an elastic valve is provided in the drive hole in which the teeth of the sprocket are engaged. The elastic valve prevents the infiltration of soil from the outside of the crawler. The resilient valve comprises at least two plates which are continuous at the longitudinal edge of the drive hole. These plates can move like a door because they are separated from the lateral edge of the drive hole. This resilient valve does not impede the drainage of soil from the inner part (inside) of the crawler. In this crawler, since the retention of soil is suppressed, the damage resulting from the biting of the soil confirmed by the conventional crawler is sufficiently prevented. With this crawler, improved durability is achieved. According to the present invention, a crawler having improved durability can be obtained.

FIG. 1 is a schematic view showing a part of a traveling device having a crawler according to an embodiment of the present invention. FIG. 2 is a plan view showing a part of the crawler of FIG. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. FIG. 4 is an enlarged plan view showing a portion of the elastic valve in FIG. FIG. 5 is an enlarged sectional view showing a portion of the elastic valve in FIG. FIG. 6 is an enlarged cross-sectional view showing a modified example of the elastic valve. FIG. 7 is an enlarged cross-sectional view showing another modified example of the elastic valve. FIG. 8 is an enlarged plan view showing still another modification of the elastic valve. FIG. 9 is an enlarged plan view showing still another modification of the elastic valve. FIG. 10 is an enlarged plan view showing still another modification of the elastic valve. FIG. 11 is an enlarged plan view showing still another modified example of the elastic valve. FIG. 12 is an enlarged plan view showing still another modification of the elastic valve.

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

  FIG. 1 shows a traveling device 4 having a crawler 2 according to an embodiment of the present invention. The traveling device 4 includes a sprocket 6. The sprocket 6 is disk-shaped. The sprocket 6 has a large number of teeth 8 at its periphery. These teeth 8 are arranged at a constant pitch along the periphery. Although not shown, in addition to the sprocket 6, the traveling device 4 includes an idler and a plurality of rolling wheels. As such a traveling device 4, an agricultural machine such as a combine and a construction machine such as a backhoe are exemplified.

  A part of the crawler 2 is shown in FIG. In FIG. 2, the left and right direction is the width direction of the crawler 2. The vertical direction is the length direction of the crawler 2. The longitudinal direction of the crawler 2 is also the rotational direction of the crawler 2 in the traveling device 4. The direction perpendicular to the paper surface is the thickness direction of the crawler 2. The front side of the paper is the outside of the crawler 2, and the back of the paper is the inside of the crawler 2.

  The cross section of the crawler 2 along the III-III line of FIG. 2 is shown by FIG. In FIG. 3, the left and right direction is the width direction of the crawler 2. The vertical direction is the thickness direction of the crawler 2. The lower side of the sheet is the outer side of the crawler 2, and the upper side of the sheet is the inner side of the crawler 2. The direction perpendicular to the paper surface is the length direction of the crawler 2 (or the rotation direction of the crawler 2).

  The crawler 2 is in the form of an endless belt. The crawler 2 constitutes a loop. The outside of the crawler 2 means the outside of this loop, and the inside of the crawler 2 means the inside of this loop.

  The crawler 2 comprises a belt 10, a number of lugs 12 and a number of guides 14. The belt 10 extends in the length direction. In this longitudinal direction, the belt 10 is not provided with an end. The belt 10 constitutes a loop. As shown in FIG. 1, a sprocket 6 abuts on this belt 10 from the inside.

  A number of lugs 12 are spaced along the length. The lugs 12 project outwardly from the belt 10. The lugs 12 extend in the width direction. The lugs 12 contribute to the traction.

  As shown in FIG. 2, in this crawler 2 the width of the lugs 12 is smaller than the width of the belt 10. In this crawler 2, a lug 12a extending from one end 16a of the belt 10 to the other end 16b is referred to as a first lug. The lug 12b extending from the other end 16b of the belt 10 towards its one end 16a is referred to as the second lug. In the crawler 2, the first lugs 12a and the second lugs 12b are alternately arranged in the length direction.

  A number of guides 14 are spaced apart in the longitudinal direction. In the width direction, two guides 14 are spaced apart. The two guides 14 aligned in the width direction are referred to as a guide pair. In this crawler 2, a large number of guide pairs are spaced apart in the length direction.

  In the crawler 2, the guide 14 protrudes inward from the belt 10. The guide 14 is disposed so as to sandwich the sprocket 6 when the crawler 2 is in use. The guide 14 restrains the movement of the sprocket 6. Although not shown, the guide 14 passes between a pair of rolling wheels.

  The crawler 2 further includes a number of drive holes 18 and a number of elastic valves 20. The drive holes 18 are spaced apart in the longitudinal direction. In this crawler 2, a drive hole 18 is disposed between one lug 12 and another lug 12 located next to the one lug 12. The drive hole 18 is located at the center of the belt 10 in the width direction. The drive hole 18 penetrates the belt 10 in the thickness direction. As shown in FIG. 1, the teeth 8 of the sprocket 6 engage in the drive holes 18. The crawler 2 is provided with a large number of drive holes 18 in which the teeth 8 of the sprocket 6 are engaged respectively.

  A portion of the drive hole 18 of the crawler 2 is shown in FIG. In FIG. 4, the left and right direction is the width direction of the crawler 2. The vertical direction is the length direction of the crawler 2. The direction perpendicular to the paper surface is the thickness direction of the crawler 2.

  In this crawler 2, as shown in FIG. 4, the shape of the drive hole 18 is rectangular. The drive hole 18 has a pair of lateral edges 22 and a pair of longitudinal edges 24. Each lateral edge 22 extends in the width direction. Each longitudinal edge 24 extends in the longitudinal direction. The drive hole 18 includes a pair of transverse edges 22 extending in the width direction and a pair of longitudinal edges 24 extending in the longitudinal direction.

  In the crawler 2, each of the multiple elastic valves 20 is located inside the drive hole 18. As shown in FIG. 4, substantially the entire drive hole 18 is closed by the elastic valve 20 with some clearance.

  In the crawler 2, the elastic valve 20 is composed of two plates 26. In this elastic valve 20, these plates 26 are arranged in parallel in the width direction. In the crawler 2, the elastic valve 20 may be provided with at least two plates 26, and the elastic valve 20 may be configured by three or more plates 26.

  As shown in FIG. 1, the crawler 2 is largely curved by abutment with the sprocket 6. In the crawler 2, as described above, the elastic valve 20 is provided with at least two plates 26. Since the elastic valve 20 is divided into a plurality of members, the influence of the elastic valve 20 on the degree of curvature is small. Even if the plate 26 constituting the elastic valve 20 has a large thickness, the crawler 2 can be easily bent. The elastic valve 20 easily contributes to the bending of the crawler 2.

  In the crawler 2, one plate 26 extends inward in the width direction from one longitudinal edge 24 of the drive hole 18. The other plate 26 extends inward in the width direction from the other longitudinal edge 24 of the drive hole 18. In the crawler 2, the respective plates 26 extend inwardly from the longitudinal edge 24 in the width direction. The widthwise center of the above-described belt 10 is located between the end 28 of one plate 26 and the end 28 of the other plate 26.

  Although not described in detail, the crawler 2 is configured by coating a metal part such as a core metal with a crosslinked rubber. In the present invention, the portion 30 made of this crosslinked rubber, in other words, the covering material, is referred to as a main body.

  The crawler 2 is provided with a large number of core metals 32 as components, in addition to a main body 30 made of a crosslinked rubber. The cored bar 32 has a plate shape. The cored bar 32 extends in the width direction. In this crawler 2, a large number of core metals 32 are arranged at intervals in the length direction. As shown in FIGS. 1 and 2, the core metal 32 is located at a portion of the lug 12. In the crawler 2, the core metal 32 is embedded in the main body 30.

  Although not shown, the crawler 2 further includes a pair of tensile bodies as parts. Each tensile body is disposed on the side of the lug 12 of the widthwise outer portion (wing) of the metal core 32. The tensile body extends longitudinally and constitutes a loop.

  The components of the crawler 2 are not limited to the main body 30, the core metal 32, and the tensile body. The crawler 2 can include other components other than the core metal 32, the main body 30, and the tensile body, as needed.

  In the crawler 2, an elastic valve 20 is provided in a drive hole 18 in which the teeth 8 of the sprocket 6 are engaged. As described above, the elastic valve 20 closes substantially the entire drive hole 18. The elastic valve 20 prevents the infiltration of soil from the outside of the crawler 2. The resilient valve 20 comprises at least two plates 26, which are continuous at the drive hole 18 and at their longitudinal edges 24. These plates 26 are separated from the lateral edge 22 of the drive hole 18. These plates 26 can move like a door. In this crawler 2, the elastic valve 20 does not prevent the discharge of the soil from the inner part (hereinafter, the inside) of the crawler 2. The soil is less likely to stay inside the crawler 2. The crawler 2 is sufficiently prevented from being damaged due to the biting of the soil as observed in the conventional crawler. In this crawler 2, improvement in durability is achieved. According to the present invention, the crawler 2 in which the improvement of durability is achieved is obtained.

  A cross section of the belt 10 as part of the crawler 2 is shown in FIG. In FIG. 5, the left and right direction is the width direction of the crawler 2. The vertical direction is the thickness direction of the crawler 2. The lower side of the sheet is the outer side of the crawler 2, and the upper side of the sheet is the inner side of the crawler 2. The direction perpendicular to the paper is the length direction of the crawler 2.

  As shown in FIG. 5, in the cross section of the belt 10 of the crawler 2, the plate 26 constituting the elastic valve 20 has a tapered shape from the root 34 toward the tip 28. In this crawler 2, the portion of the root 34 of the plate 26 is hard, and the portion of its tip 28 is soft. The portion of the hard root 34 contributes to the prevention of the intrusion of soil from the outside, and the portion of the soft tip 28 contributes to the drainage of the soil from the inside. Since soil does not easily stay inside, damage due to soil biting is effectively prevented. The crawler 2 is excellent in durability. From this point of view, in the crawler 2, in the cross section of the belt 10, the plate 26 constituting the elastic valve 20 preferably has a tapered shape from the root 34 toward the tip 28.

  In the crawler 2, the plate 26 comprises an inner surface 36 and an outer surface 38. The inner surface 36 is located inside in the thickness direction of the crawler 2. In the cross section of the belt 10 shown in FIG. 5, the contour of this inner surface 36 is represented by a straight line. The inner surface 36 is inclined with respect to the width direction. The outer surface 38 is located outside in the thickness direction of the crawler 2. In the cross section of the belt 10 shown in FIG. 5, the contour of this outer surface 38 is represented by a straight line. The outer surface 38 is inclined with respect to the width direction.

  In FIG. 5, the symbol θu represents the angle that the inner surface 36 makes with the width direction, that is, the inclination angle of the inner surface 36. In FIG. 5, the symbol θu represents the angle that the inner surface 36 makes with the width direction, that is, the inclination angle of the inner surface 36. If the contour of the inner surface 36 or the outer surface 38 is not a straight line but is expressed using a curve or the like, the inclination angle of the straight line obtained by connecting the outer end and the inner end in the width direction of the inner surface 36 or the outer surface 38 The inclination angle θu or the inclination angle θs is represented.

  As described above, the inner surface 36 is inclined with respect to the width direction. If the plate 26 functions as the elastic valve 20, the plate 26 may be configured such that the inner surface 36 extends in the width direction. In other words, the inclination angle θu of the inner surface 36 is 0 ° or more. The inner surface 36 of the plate 26 is preferably inclined with respect to the width direction from the viewpoint that the retention of soil inside the crawler 2 is suppressed and the biting of the soil is effectively prevented. Specifically, the inclination angle θu of the inner surface 36 is preferably 5 ° or more, and more preferably 50 ° or less.

  As described above, the outer surface 38 is inclined with respect to the width direction. If the plate 26 functions as the elastic valve 20, the plate 26 may be configured such that the outer surface 38 extends in the width direction. In other words, the inclination angle θs of the outer surface 38 is 0 ° or more. It is preferable that the outer surface 38 of the plate 26 be inclined with respect to the width direction from the viewpoint that the retention of the soil inside the crawler 2 is suppressed and the biting of the soil is effectively prevented. Specifically, the inclination angle θs of the outer surface 38 is preferably 5 ° or more, and more preferably 50 ° or less.

  As shown in FIG. 5, in this crawler 2, the inclination of the inner surface 36 with respect to the width direction is larger than the inclination of the outer surface 38 with respect to the width direction. In other words, the inclination angle θu of the inner surface 36 is larger than the inclination angle θs of the outer surface 38. In this crawler 2, the plate 26 is less likely to bend from the outside to the inside, and is more likely to bend from the inside to the outside. In the crawler 2, the elastic valve 20 effectively contributes to the prevention of the intrusion of soil from the outside and the discharge of the soil from the inside. In the crawler 2, since the soil does not easily stay inside, biting of the soil is effectively prevented. The crawler 2 is excellent in durability. From this point of view, in the crawler 2, the inclination of the inner surface 36 with respect to the width direction is preferably larger than the inclination of the outer surface 38 with respect to the width direction.

  As described above, in the crawler 2, preferably, the inclination angle θu of the inner surface 36 is larger than the inclination angle θs of the outer surface 38. Thereby, the bite of the soil is effectively prevented, and therefore, the crawler 2 can improve the durability. From this viewpoint, the difference (θu−θs) between the inclination angle θu of the inner surface 36 and the inclination angle θs of the outer surface 38 is preferably 10 ° or more, and preferably 30 ° or less. As for this difference ((theta) u- (theta) s), 15 degrees or more are more preferable, and 25 degrees or less are more preferable.

  In the crawler 2, a gap is provided between the tip 28 of one plate 26 and the tip 28 of the other plate 26. The movement of the respective plates 26 is smooth since one plate 26 and the other plate 26 do not overlap in the thickness direction. In this crawler 2, in particular, drainage of soil from the inside is promoted. In the crawler 2, since the soil does not easily stay inside, biting of the soil is effectively prevented. The crawler 2 is excellent in durability. From this point of view, in the crawler 2, it is preferable that a gap be provided between the tip 28 of one plate 26 and the tip 28 of the other plate 26.

  As described above, in the crawler 2, substantially the entire drive hole 18 is closed by the elastic valve 20. This effectively suppresses the intrusion of soil from the outside. From this viewpoint, in the crawler 2, the ratio of the area of the elastic valve 20 to the area of the drive hole 18 is preferably 70% or more, more preferably 75% or more, and still more preferably 80% or more. If the drive hole 18 is completely closed by the elastic valve 20, there is a concern that the soil will not be easily discharged from the inside. In light of easiness of soil discharge, the ratio is preferably 99% or less, more preferably 95% or less, and still more preferably 90% or less. The areas of the drive hole 18 and the elastic valve 20 are specified in the plan view of the crawler shown in FIG.

  In the crawler 2, the plate 26 can have various cross-sectional shapes as long as the plate 26 is not easily bent from the outside to the inside and is easily bent from the inside to the outside.

  FIG. 6 shows a modified example of the cross-sectional shape of the plate 26 constituting the elastic valve 20 (the cross-sectional shape of the plate 26b). In FIG. 6, the left and right direction is the width direction of the crawler 2. The vertical direction is the thickness direction of the crawler 2. The lower side of the sheet is the outer side of the crawler 2, and the upper side of the sheet is the inner side of the crawler 2. The direction perpendicular to the paper is the length direction of the crawler 2.

  As shown in FIG. 6, in the cross section of the belt 10, the contour of the outer surface 38b of the plate 26b is represented by a straight line. In particular, the outer surface 38b whose contour is represented by a straight line extends in the width direction. The contour of the inner surface 36b of the plate 26b includes an arc. In other words, the inner surface 36b is a curved surface. Particularly, in the elastic valve 20 shown in FIG. 6, the arc included in the contour of the inner surface 36b extends from the root 34 of the plate 26b toward the tip 28. In the elastic valve 20, the plate 26b is configured such that the cross-sectional shape thereof is tapered from the root 34 toward the tip 28 by the flat outer surface 38b and the curved inner surface 36b. In this plate 26b, like the plate 26 shown in FIG. 5, the portion of the root 34 is hard and the portion of the tip 28 is soft. Moreover, since the contour of the inner surface 36b is configured to include a circular arc, the inclination of the inner surface 36b with respect to the width direction is larger than the inclination of the outer surface 38b with respect to the width direction. Also in the elastic valve 20, the plate 26b does not easily bend from the outside to the inside, and easily bends from the inside to the outside. In the crawler 2 having the elastic valve 20, the elastic valve 20 effectively contributes to the prevention of the intrusion of soil from the outside and the discharge of the soil from the inside. In the crawler 2, since the soil does not easily stay inside, biting of the soil is effectively prevented. The crawler 2 is excellent in durability. From this point of view, in the cross section of the belt 10 of the crawler 2, the contour of the outer surface 38b of the plate 26b is represented by a straight line, the contour of the inner surface 36b of the plate 26b includes a circular arc, and the circular arc is the plate 26b. The plate 26 b of the resilient valve 20 may be configured to extend from the root 34 towards the tip 28.

  FIG. 7 shows another modified example of the cross-sectional shape of the plate 26 constituting the elastic valve 20 (the cross-sectional shape of the plate 26c). In FIG. 7, the left and right direction is the width direction of the crawler 2. The vertical direction is the thickness direction of the crawler 2. The lower side of the sheet is the outer side of the crawler 2, and the upper side of the sheet is the inner side of the crawler 2. The direction perpendicular to the paper is the length direction of the crawler 2.

  In the elastic valve 20 shown in FIG. 7, in the cross section of the belt 10, the plate 26c is configured such that its thickness gradually decreases from the root 34 to the tip 28 of the plate 26c. The contour of the outer surface 38c of the plate 26c is represented by a straight line. In particular, the outer surface 38c whose contour is represented by a straight line extends in the width direction. Since the outer surface 38c is flat, in the elastic valve 20, a plurality of steps are formed on the inner surface 36c of the plate 26c. In the elastic valve 20, the plate 26c is configured such that its cross-sectional shape exhibits a tapered shape from the root 34 toward the tip 28 by the flat outer surface 38c and the inner surface 36c provided with a plurality of steps. ing. In this plate 26c, like the plate 26 shown in FIG. 5, the portion of the root 34 is hard and the portion of the tip 28 is soft. Moreover, by providing the plurality of steps on the inner surface 36c, the plate 26c is configured so that the thickness of the plate 26c gradually decreases from the root 34 toward the tip 28, the inner surface 36c in the width direction The inclination is larger than the inclination of the outer surface 38c with respect to the width direction. Also in this elastic valve 20, the plate 26c does not easily bend from the outside to the inside, and easily bends from the inside to the outside. In the crawler 2 having the elastic valve 20, the elastic valve 20 effectively contributes to the prevention of the intrusion of soil from the outside and the discharge of the soil from the inside. In the crawler 2, since the soil does not easily stay inside, biting of the soil is effectively prevented. The crawler 2 is excellent in durability. From this point of view, in the cross section of the belt 10 of the crawler 2, the contour of the outer surface 38c of the plate 26c is represented by a straight line, and the thickness of the plate 26c gradually decreases from the root 34 to the tip 28 of the plate 26c. The plate 26c may be configured to be as follows.

  As shown in FIG. 4, the planar shape of the plate 26 constituting the elastic valve 20 is rectangular. The portion of the tip 28 of the plate 26 extends linearly in the longitudinal direction. In the crawler 2, if the plate 26 can be smoothly deformed by the action of a force, the portion of the tip 28 of the plate 26 can have various shapes.

  Each of FIGS. 8, 9, 10 and 11 shows a modification of the planar shape of the plate 26 constituting the elastic valve 20. As shown in FIG. In these figures, the left-right direction is the width direction of the crawler 2. The vertical direction is the length direction of the crawler 2. The direction perpendicular to the paper surface is the thickness direction of the crawler 2.

  In the elastic valve 20 shown in FIG. 8, the portion of the tip 28 of the plate 26d has a zigzag shape. In FIG. 9, the portion of the tip 28 of the plate 26e has an S shape. In FIG. 10, the portion of the tip 28 of the plate 26f is stepped. In the plate 26g shown in FIG. 11, a recess 40 is provided at the longitudinal center of the tip 28 portion.

  In the plate 26, the shape of the portion of the tip 28 contributes to the rigidity of the portion of the tip 28. In particular, the tip 28 portion of the plate 26 is softer than the root 34 portion. Therefore, the shape of the portion of the tip 28 is likely to be reflected in the rigidity in the length direction of the portion of the tip 28. In this crawler 2, by adjusting the shape of the portion of the tip 28, it is possible to control the discharge position of the soil discharged from the inside. From this point of view, in the crawler 2, the portion of the tip 28 of the plate 26 may have a zigzag shape. The portion of the tip 28 of the plate 26 may be S-shaped. Furthermore, the portion of the tip 28 of the plate 26 may be stepped. A recess 40 may be provided at the center of the tip 28 in the longitudinal direction.

  A modified example of the elastic valve 20 (hereinafter, the elastic valve 20b) is shown in FIG. In FIG. 12, the left and right direction is the width direction of the crawler 2. The vertical direction is the length direction of the crawler 2. The direction perpendicular to the paper surface is the thickness direction of the crawler 2.

  The elastic valve 20 b includes four plates 26. As shown in FIG. 12, two plates 26 extend inward in the width direction from one longitudinal edge 24, and the remaining two plates 26 extend in the width direction from the other longitudinal edge 24. It extends in the direction. At each longitudinal edge 24, the two plates 26 are longitudinally juxtaposed. Since this elastic valve 20b is composed of four plates 26, it is softer than the elastic valve 20 composed of two plates 26 shown in FIG. The influence of the elastic valve 20b on the degree of curvature of the crawler 2 is quite small. Even if the plate 26 constituting the elastic valve 20b has a considerable thickness, the crawler 2 can be easily curved. The elastic valve 20 b easily contributes to the bending of the crawler 2. Since deformation of each plate 26 is easy, this elastic valve 20b also contributes to the drainage of soil from the inside. The elastic valve 20b effectively contributes to the prevention of the biting of the soil. From this point of view, in the crawler 2, the number of the plates 26 extending inward in the width direction from the longitudinal edge 24 and juxtaposed in the length direction may be set to three or more. In other words, in the crawler 2, the elastic valve 20b may include at least two plates 26 extending inward from one longitudinal edge 24, and these plates 26 may be juxtaposed in the longitudinal direction.

  In the crawler 2, the hardness of the plate 26 is preferably 50 or more, and preferably 80 or less. The plate 26 of which hardness is set to 50 or more is moderately hard. The elastic valve 20 having the plate 26 contributes to preventing the intrusion of soil from the outside. The plate 26 whose hardness is set to 80 or less is moderately soft. The elastic valve 20 having the plate 26 promotes drainage of soil from the inside. The elastic valve 20 having the plate 26 whose hardness is set to 50 or more and 80 or less does not prevent the soil from being discharged from the inside while suppressing the intrusion of the soil into the inside. Since the damage due to the biting of the soil is effectively prevented, the durability of the crawler 2 is further improved.

  In the present invention, the hardness is measured by a durometer of type A according to the definition of "JIS K6253". Specifically, at a temperature of 23 ° C., the durometer is pressed against the cross section shown in FIG. 3, and the hardness is measured.

  The technique of providing an elastic valve in the drive hole of the crawler described above can be applied to various types of crawlers.

Reference Signs List 2 crawler 4 traveling device 6 sprocket 8 tooth 10 belt 12 12a, 12b lug 18 drive hole 20 20b elastic valve 22 ... Horizontal edge 24 ... Longitudinal edge 26, 26b, 26c, 26d, 26e, 26f, 26g ... Plate 28 ... Tip of plate 34 34 ... Root of plate 26 36, 36b, 36c ... · · Inner surface 38, 38b, 38c · · · Outer surface 40 · · ·

Claims (7)

The belt includes: a belt on which a sprocket abuts from the inside; a plurality of drive holes in which the teeth of the sprocket respectively engage; and an elastic valve positioned inside the respective drive holes;
The drive hole includes a pair of transverse edges extending in the width direction and a pair of longitudinal edges extending in the longitudinal direction,
The resilient valve comprises at least two plates,
Each plate extends inwardly from the longitudinal edge in the width direction,
A crawler, wherein the plate is separated from the lateral edge. The resilient valve comprises at least two of the plates extending inwardly from one of the longitudinal edges;
The crawler according to claim 1, wherein the plates are juxtaposed longitudinally.   The crawler according to claim 1 or 2, wherein the plate has a tapered shape from the root to the tip in the cross section of the belt. The plate has an inner surface located on the inner side and an outer surface located on the outer side;
The crawler according to claim 3, wherein the inclination of the inner surface with respect to the width direction is larger than the inclination of the outer surface with respect to the width direction.   The crawler according to claim 4, wherein the contour of the outer surface and the contour of the inner surface are represented by straight lines in the cross section of the belt. In the section of the belt, the contour of the outer surface is represented by a straight line, and the contour of the inner surface includes a circular arc,
The crawler according to claim 4, wherein the arc extends from the root of the plate toward the tip. In the cross section of the belt, the contour of the outer surface is represented by a straight line,
The crawler according to claim 4, wherein the plate is configured such that its thickness decreases gradually from the root to the tip of the plate.

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