Elastomeric endless track and method for making same

Abstract

An elastomeric track for a track system is disclosed. The elastomeric track has a carcass and a plurality of longitudinally spaced lugs. The carcass has an inner surface engageable by at least one wheel assembly and an outer surface engageable with a ground surface. The carcass is made of at least a first elastomeric material. The plurality of longitudinally spaced lugs protrude from the inner surface and define a plurality of inter-lug sections located between adjacent longitudinally spaced lugs. At least some of the plurality of inter-lug sections include zones made of at least a second elastomeric material. A method for manufacturing an elastomeric track for a track system is also disclosed.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 282,269, entitled “Elastomeric Endless Track and Method for Manufacturing Same,” filed November 23, 2021, and incorporated herein by reference in its entirety.

[0002] The present technology relates to elastomeric tracks, methods for manufacturing elastomeric tracks, and track systems including such elastomeric tracks. [Background technology]

[0003] For example, certain vehicles, such as agricultural vehicles (e.g., harvesters, combines, tractors, etc.), construction vehicles (e.g., bulldozers, front end loaders, etc.), all-terrain vehicles (ATVs), and utility task vehicles (UTVs), are used on soft, slippery, and / or uneven surfaces (e.g., soil, mud, sand, ice, snow, etc.).

[0004] Traditionally, such vehicles have had large wheels with tires to move the vehicle along the ground surface. Under certain conditions, such tires may have insufficient traction on some types of ground surfaces, and because these vehicles are generally heavy, the tires may compress the ground surface in an undesirable manner due to the weight of the vehicle.

[0005] To reduce the aforementioned drawbacks, the wheels have been replaced by track systems having endless tracks.

[0006] However, conventional tracks pose several disadvantages: they can induce high rolling resistance to the track system, and the tracks can dissipate a significant amount of energy.

[0007] Therefore, there is a need for a track that can alleviate the above-mentioned problems. Summary of the Invention [Problem to be solved by the invention]

[0008] The objective of the present technology is to remedy at least some of the disadvantages present in the prior art. [Means for solving the problem]

[0009] In the context of the following description, "outwardly" or "outwardly" means away from the longitudinal center plane of the track system, and "inwardly" or "inwardly" means toward the longitudinal center plane. Additionally, in the context of the following description, "longitudinally" means in a direction parallel to the longitudinal center plane of the track system in a plane parallel to the flat, level ground, "laterally" means in a direction perpendicular to the longitudinal center plane in a plane parallel to the flat, level ground, and "substantially vertically" means in a direction contained within the longitudinal center plane along a height of the track system that is substantially perpendicular to the flat, level ground. In the following description and the accompanying figures, the track system is configured to be mounted on the right side of a vehicle chassis.

[0010] In accordance with one aspect of the present technology, an elastomeric endless track for a track system is provided. The endless track includes a carcass and a plurality of longitudinally spaced lugs. The carcass has an inner surface engageable by at least one wheel assembly and an outer surface engageable with a ground surface. The carcass is made of at least a first elastomeric material. The plurality of longitudinally spaced lugs protrude from the inner surface and define a plurality of inter-lug sections located between adjacent longitudinally spaced lugs. At least some of the plurality of inter-lug sections include zones made of at least a second elastomeric material.

[0011] In some embodiments, the second elastomeric material is less viscous than the first elastomeric material.

[0012] In some embodiments, each zone of the plurality of inter-lug sections extends longitudinally from a bottom portion of a first lug to a bottom portion of a second lug adjacent the first lug.

[0013] In some embodiments, the width of each zone of the plurality of interlug sections is the same as the width of the plurality of longitudinally spaced lugs.

[0014] In some embodiments, the width of each zone of the plurality of interlug sections spans at least 50% of the width of the carcass.

[0015] In some embodiments, the inner surface defines a first wheel engaging portion on a first side of the plurality of longitudinally spaced lugs and a second wheel engaging portion on a second side of the plurality of longitudinally spaced lugs, each zone of the plurality of inter-lug sections extending from the first wheel engaging portion to the second wheel engaging portion.

[0016] In some embodiments, each zone of the plurality of inter-lug sections has a leading portion, a middle portion, and a trailing portion, where the leading portion has a first thickness, the middle portion has a second thickness, and the trailing portion has a third thickness, where the first and third thicknesses are less than the second thickness.

[0017] In some embodiments, the intermediate portion of each zone of the plurality of inter-lug sections is approximately in the center of the inter-lug section.

[0018] In some embodiments, a medial portion of each zone of the plurality of inter-lug sections is offset from a center of the inter-lug section.

[0019] In some embodiments, each zone of the plurality of inter-lug sections has a leading portion, an intermediate portion, and a trailing portion, wherein the leading portion has a first thickness, the intermediate portion has a second thickness, and the trailing portion has a third thickness, and the first, second, and third thicknesses are the same.

[0020] In some embodiments, the first, second, and third thicknesses are 0.1 inches.

[0021] In some embodiments, a ratio of the thickness of the second elastomeric material to the thickness of the first elastomeric material in some of the plurality of inter-lug sections is at least about 5%.

[0022] In some embodiments, a ratio of the thickness of the second elastomeric material to the thickness of the first elastomeric material in some of the plurality of inter-lug sections is at least about 30%.

[0023] In some embodiments, a ratio of the thickness of the second elastomeric material to the thickness of the first elastomeric material in some of the plurality of inter-lug sections is at least about 45%.

[0024] In some embodiments, each zone of the plurality of inter-lug sections defines a generally rectangular shape.

[0025] In some embodiments, each zone of the plurality of inter-lug sections has a protective layer, the protective layer being made from a third material.

[0026] In some embodiments, the third material is the same as the first elastomeric material.

[0027] In some embodiments, the first deformation energy of the first elastomeric material is greater than the second deformation energy of the second elastomeric material.

[0028] In some embodiments, upon deformation of the first and second elastomeric materials, the first elastomeric material dissipates more heat than the second elastomeric material.

[0029] In some embodiments, upon deformation of the track, each zone of the plurality of inter-lug sections dissipates less energy than a correspondingly sized zone of the carcass.

[0030] In some embodiments, the first elastomeric material has a first mechanical property and the second elastomeric material has a second mechanical property, the first mechanical property being different from the second mechanical property.

[0031] In some embodiments, the first elastomeric material has a first viscoelastic property and the second elastomeric material has a second viscoelastic property, the first viscoelastic property being different from the second viscoelastic property.

[0032] In some embodiments, the at least one second elastomeric material is a composite elastomeric material.

[0033] In some embodiments, the presence of multiple inter-lug sections reduces the rolling resistance of the track by about 5%.

[0034] In some embodiments, the rolling resistance of the track is less than about 70 Nm when the temperature within the track is about 40°C.

[0035] In some embodiments, the first elastomeric material has a first storage to loss modulus ratio and the second elastomeric material has a second storage to loss modulus ratio, the first storage to loss modulus ratio being greater than the second storage to loss modulus ratio.

[0036] In another aspect of the present technology, there is provided a track system including a frame, a wheel assembly rotatably connected to the frame, and an elastomeric endless track according to the above aspect or according to one or more of the above aspects and embodiments. The endless track surrounds the frame and the wheel assembly.

[0037] In some embodiments, the wheel assembly includes a sprocket wheel assembly rotatably connected to the frame and operably connectable to the drive shaft, the sprocket wheel assembly configured to engage a plurality of longitudinally spaced lugs.

[0038] In some embodiments, the track system has a rolling resistance and at least some of the inter-lug sections are configured to dissipate less deformation energy than a remainder of the carcass, thereby reducing rolling resistance.

[0039] In accordance with another aspect of the present technology, a method for manufacturing an elastomeric endless track for a track system is provided. The method includes forming a carcass having a plurality of longitudinally spaced lugs, the carcass having an inner surface configured to engage at least one wheel assembly and an outer surface configured to engage a ground surface. The carcass is made of at least a first elastomeric material. The longitudinally spaced lugs define a plurality of inter-lug sections located between two adjacent longitudinally spaced lugs. At least some of the plurality of inter-lug sections include zones made of at least a second elastomeric material.

[0040] In the context of this specification, unless otherwise specified, the words "first," "second," "third," etc. are used as adjectives only for the purpose of enabling distinction between the nouns they modify and not for the purpose of describing a particular relationship between those nouns.

[0041] Please note that as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0042] As used herein, the term "about" in the context of a given value or range refers to a value or range that is within 20%, preferably within 10%, and more preferably within 5% of the given value or range.

[0043] As used herein, the term "and / or" should be interpreted as a specific disclosure of each of the two specified features or components, with or without the other. For example, "A and / or B" should be interpreted as a specific disclosure of (i) A, (ii) B, and (iii) each of A and B, as if each were individually set forth herein.

[0044] Implementations of the present technology each have at least one, but not necessarily all, of the above-mentioned objects and / or aspects, and it should be understood that some aspects of the present technology that arise out of an attempt to achieve the above-mentioned object may not meet that object and / or may meet other objects not specifically recited herein.

[0045] Additional and / or alternative features, aspects, and advantages of implementations of the present technology will become apparent from the following description, the accompanying drawings, and the appended claims.

[0046] For a better understanding of the present technology as well as other aspects and further features thereof, reference is made to the following description taken in conjunction with the accompanying drawings, in which: [Brief description of the drawings]

[0047] [Figure 1] FIG. 1 is a right side elevation view of a harvester having a track system with endless tracks. [Diagram 2] FIG. 2 is a top, front, left side perspective view of a portion of the track of FIG. 1; [Diagram 3] FIG. 3 is a top plan view of a portion of the track of FIG. [Figure 4] FIG. 3 is a bottom, rear, right side perspective view of a portion of the track of FIG. 2. [Figure 5A] FIG. 5A is a cross-sectional view of a portion of the track taken along line 5A-5A of FIG. [Figure 5B] FIG. 5B is an enlarged view of a section of a portion of the track taken from FIG. 5A. [Figure 6]FIG. 2 is a top plan view of a portion of an alternative embodiment of the endless track of FIG. [Figure 7A] FIG. 7A is a cross-sectional view taken along line 7A-7A in FIG. 6. [Figure 7B] FIG. 7B is an enlarged view of a section of a portion of the track taken from FIG. 7A. [Figure 8] FIG. 2 is an enlarged view of a section of an alternative embodiment of the endless track of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] The present disclosure is not limited in its application to the details of construction and arrangement of components set forth in the following description or illustrated in the drawings. The present disclosure is capable of other embodiments and of being practiced or carried out in various ways. Moreover, the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," "having," "containing," "involving," and variations thereof herein means the inclusion of the items listed thereafter and optionally additional items. In the following description, like reference numerals refer to like elements.

[0049] The present technology relates to various embodiments of an endless track and is described with reference to a track system.

[0050] Referring to FIG. 1, a harvester 40 is shown. The harvester 40 has a frame 42 that houses an engine 44 (shown diagrammatically). The harvester 40 also has left and right rear wheels 46 and left and right track systems 50 (only the right rear wheel 46 and the right track system 50 are shown in the accompanying figures). It is contemplated that in some embodiments, the harvester 40 may have more than two track systems. The engine 44 is operably connected to the left and right track systems 50. It is contemplated that in some embodiments, the engine 44 may be operably connected to the rear wheels 46. It is understood that the present technology may be used with other vehicles, such as bulldozers, skid steer loaders, excavators, and / or compact track loaders. Additionally, the present technology may also be used with other vehicles, such as all-terrain vehicles, snowmobiles, side-by-side vehicles, or utility-terrain vehicles. It is further contemplated that the present technology may be used with industrial and military vehicles. It is also contemplated that the present technology may be used with trailers or other non-motorized vehicles.

[0051] 1 , the track system 50 includes a sprocket wheel assembly 60 operatively connected to an axle (not shown) of the harvester 40 such that as the axle rotates, the sprocket wheel assembly 60 also rotates, thereby driving the track system 50. In some embodiments, it is contemplated that the sprocket wheel assembly 60 may be configured to connect to a non-drive axle of the vehicle. The sprocket wheel assembly 60 defines a plurality of recesses 62. The plurality of recesses 62 are defined circumferentially about the circumference of the sprocket wheel assembly 60. The recesses 62 are configured to engage lugs 108 on an inner surface 104 of the endless track 100, as described in more detail below.

[0052] The track system also includes a frame 70 rotatably connected to and disposed laterally inboard of the sprocket wheel assembly 60. In other embodiments, it is contemplated that the frame 70 may be disposed laterally outboard from the sprocket wheel assembly 60. The frame 70 includes a main frame member 72, a leading frame member 74, and a trailing frame member 76, which are pivotally connected to the main frame member 72.

[0053] The track system 50 includes wheel assemblies. More precisely, the track system 50 includes, in addition to the sprocket wheel assembly 60, a front idler wheel assembly 80, a rear idler wheel assembly 82, and three support wheel assemblies 84a, 84b, 84c disposed longitudinally between the front and rear idler wheel assemblies 80, 82. It is contemplated that in some embodiments, the track system 50 may have more or less than three support wheel assemblies.

[0054] Front idler wheel assembly 80 and support wheel assembly 84a are rotatably connected to the leading frame member 74. Support wheel assemblies 84b, 84c are connected to form a tandem 86, which is pivotally connected to the trailing frame member 76. Rear idler wheel assembly 82 is also rotatably connected to the trailing frame member 76. Thus, to some extent, the track system 50 is configured to adapt to obstacles that are encountered.

[0055] Each one of the front and rear idler wheel assemblies 80, 82, and support wheel assemblies 84a, 84b, 84c has two laterally spaced wheels, such that each one of the front and rear idler wheel assemblies 80, 82, and support wheel assemblies 84a, 84b, 84c has a left wheel and a right wheel (only the right wheel of each of the wheel assemblies is shown in FIG. 1). In some embodiments, it is contemplated that one or more of the front and rear idler wheel assemblies 80, 82, and support wheel assemblies 84a, 84b, 84c may be configured to have a single wheel or three or more wheels.

[0056] In some embodiments, it is contemplated that the track system 50 may include a tensioner configured to adjust the tension of the endless track 100 .

[0057] Track system 50 also includes endless tracks 100, which will now be described in more detail with reference to Figures 2-4. Endless tracks 100 extend around the components of track system 50 such that tracks 100 encircle sprocket wheel assembly 60, frame 70, front and rear idler wheel assemblies 80, 82, and support wheel assemblies 84a, 84b, 84c.

[0058] In some embodiments, the track 100 is an elastomeric track and includes a carcass 102 and a plurality of longitudinally spaced lugs 108 .

[0059] The carcass 102 has an inner surface 104 configured to be engaged by the front and rear idler wheel assemblies 80, 82, and the support wheel assemblies 84a, 84b, 84c. The carcass 102 also has an outer surface 106 configured to engage a ground surface. The track 100 has a reinforcing cable 114 extending longitudinally and embedded in the carcass 102 between the inner surface 104 and the outer surface 106, and a reinforcing sheet 116. The reinforcing cable 114 and the reinforcing sheet 116 are configured to generally limit the longitudinal elongation and / or limit the longitudinal deformation of the carcass 102. Thus, the reinforcing cable 114 and the reinforcing sheet 116 reinforce the track 100, which may help reduce the likelihood that the track 100 will tear and / or be damaged, thereby increasing the lifespan of the track 100. It is contemplated that in some embodiments, the reinforcing cable 114 and / or the reinforcing sheet 116 may be omitted. The carcass 102 is made from a first elastomeric material. It is contemplated that the first elastomeric material may be a polymeric material.

[0060] 2 and 3, and focusing initially on the inner surface 104, the lugs 108 protrude from the inner surface 104. More specifically, in this embodiment, the lugs 108 are disposed approximately centrally along the width of the inner surface 104. The lugs 108 are configured to engage teeth of the sprocket wheel assembly 60. It is contemplated that in some embodiments, the carcass 102 may have two or more laterally spaced sets of longitudinally spaced lugs 108. An inter-lug section 110 is defined longitudinally between two adjacent lugs 108. Thus, between each two adjacent lugs 108, there is an inter-lug section 110. Each of the inter-lug sections 110 has a flexibility zone 112, which will be described in more detail below. It is contemplated that in some embodiments, the flexibility zone 112 may be present in only a portion of the inter-lug sections 110.

[0061] To the left and right of the lug 108, the inner surface 104 has wheel-engaging sections 120a, 120b that are configured to engage left and right wheels of the front and rear idler wheel assemblies 80, 82, and left and right wheels of the support wheel assemblies 84a, 84b, 84c, respectively. The wheel-engaging sections 120a, 120b, which extend longitudinally along the track 100, are generally flat. In some embodiments, laterally outward from the wheel-engaging sections 120a, 120b, the inner surface 104 may define a recess in the carcass 102, which is believed to reduce the amount of material required to manufacture the track 100 and thus, in some cases, help reduce the rolling resistance induced by the track 100.

[0062] 4, the outer surface 106 of the track 100 has ridges 124 that form a tread 126. It is contemplated that the tread 126 may vary in shape and size depending on the embodiment. In some embodiments, the tread 126 may depend on the type of vehicle to which the track system 50 is attached and / or the type of surface on which the vehicle is intended to travel. Thus, the spacing between the ridges 124 may vary depending, in part, on the surface on which the track 100 is used, the type of vehicle on which the track 100 is used, etc.

[0063] 2, 3, 5A, and 5B, the flexibility zones 112 will now be described in more detail. As mentioned above, in this embodiment, each of the inter-lug sections 110 has one flexibility zone 112, such that the track 100 has multiple flexibility zones 112. Because the multiple flexibility zones 112 are generally similar, only one flexibility zone 112 will be described herein.

[0064] Flexibility zone 112 defines a generally rectangular shape when viewed from a top plan view (FIG. 3). However, it is contemplated that in some embodiments, flexibility zone 112 may define another shape, such as an oval (FIG. 6) or a circle.

[0065] The flexibility zone 112, having a leading portion 130, an intermediate portion 132, and a trailing portion 134, extends from the bottom portion of one lug 108 to the bottom portion of an adjacent lug 108. More precisely, the flexibility zone 112 extends from the root of one of the lugs 108 to the root of the adjacent lug 108, such that the leading portion 130 begins at the root of one of the lugs 108, the trailing portion 134 ends at the root of the adjacent lug 108, and the intermediate portion 132 is approximately in the center of the inter-lug section (i.e., centered between two adjacent lugs 108). In some embodiments, the flexibility zone 112 can extend from under one of the lugs 108 to under the adjacent lug 108, such that the leading portion 130 begins under one of the lugs 108 and the trailing portion 134 ends under the adjacent lug 108.

[0066] 8, in some embodiments, the flexibility zone 112 extends from a point spaced longitudinally from one of the lugs 108 to a point spaced longitudinally from an adjacent lug 108, such that the leading portion 130 is spaced longitudinally from one of the lugs 108 and the trailing portion 134 is spaced longitudinally from the adjacent lug 108 (i.e., the flexibility zone 112 is spaced apart from the lug 108). In the embodiment shown in FIG. 8, the intermediate portion 132 is offset from the center of the inter-lug section 110.

[0067] 5A and 5B, the leading portion 130 has a thickness T1, the intermediate portion 132 has a thickness T2, the trailing portion 134 has a thickness T3, and the carcass 102 has an overall thickness T at the lug-to-lug section 10. The overall thickness T does not include the lugs 108 or the ridges 124. The thickness T2 is greater than the thicknesses T1 and T3. In some embodiments, it is contemplated that the thickness T1 can be greater than the thicknesses T2 and T3. In other embodiments, the thickness T1 can be less than the thicknesses T2 and T3. Any such variations are contemplated. The thickness ratio, defined as being of the thicknesses T1, T2, T3 to the thickness T, is about at least about 5%, at least about 6%, at least about 7%, at least about 8%, at least about 9%, at least about 10%. In other embodiments, the thickness ratio is about at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, or at least about 40%. In yet other embodiments, the thickness ratio is about at least about 45%. In some cases, the thickness ratio is defined as being that of the thicknesses T1, T2, T3 relative to the thickness of the first material.

[0068] In an alternative embodiment of the present technology shown in Figures 6, 7A and 7B, the thicknesses T1, T2, T3 are the same (i.e., the flexibility zone 112 has one uniform thickness). In this embodiment, the thicknesses T1, T2, and T3 are about 0.2 inches. It is contemplated that the thicknesses T1, T2, T3 may be greater or less than about 0.2 inches. For example, in some embodiments, the thicknesses T1, T2, T3 may be about 0.05 inches, about 0.075 inches, about 0.1 inches, about 0.125 inches, about 0.15 inches, and / or about 0.175 inches. In yet other embodiments, the thicknesses T1, T2, T3 may be about 0.4 inches, about 0.375 inches, about 0.35 inches, about 0.325 inches, about 0.3 inches, about 0.275 inches, about 0.250 inches, or about 0.225 inches. In some embodiments, the thickness ratio, defined as being that of thickness T1, T2 or T3 relative to the thickness T of the carcass 102, similar to that described above, is about at least about 5%, at least about 6%, at least about 7%, at least about 8%, at least about 9%, at least about 10%. In other embodiments, the thickness ratio is about at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, or at least about 40%. In yet other embodiments, the thickness ratio is about at least about 45%.

[0069] 3, 5A and 5B, the width of the flexibility zone 112 is approximately the same as the width of one of the lugs 108, the width of each of the lugs 108 being measured from the outermost portion of one side of the lug 108 to the outermost portion of the other side of the lug 108. The outermost portion of the lug 108 is proximate to the wheel engaging portions 120a, 120b, so that the flexibility zone 112 extends laterally from the wheel engaging portion 120a to the wheel engaging portion 120b. In some embodiments, the width of the flexibility zone 112 can vary from one of the leading portion 130, the intermediate portion 132, and the trailing portion 134 to another. For example, the width at the intermediate portion 132 can be greater than the width at the leading portion 130 and the trailing portion 134. It is contemplated that in some embodiments, the width of the flexibility zone 112 can be greater than the width of the lugs 108.

[0070] 6, 7A, and 7B, the width of the flexibility zone 112 is greater than the width of the lugs 108. In this embodiment, the flexibility zone 112 spans at least about 60% of the width of the carcass 102. In some embodiments, the flexibility zone 112 may span at least about 50% of the width of the carcass 102. In other embodiments, the flexibility zone 112 may span at least about 70% of the width of the carcass 102. The width of the flexibility zone 112 varies from the intermediate portion 132 to the leading portion 130 and the trailing portion 134 such that the width at the intermediate portion 132 is greater than the width at the leading portion 130 and the trailing portion 134.

[0071] The flexibility zone 112 also has a protective layer 140 on top of it. In some embodiments, the protective layer 140 is omitted. The protective layer 140 can protect the flexibility zone 112 from the sprocket wheel assembly 60 when the sprocket wheel assembly 60 engages the track 100. The protective layer 140 is made of a first elastomeric material. In other embodiments, it is contemplated that the protective layer 140 may be made of another material.

[0072] In some embodiments, the flexibility zone 112 is made of at least a second elastomeric material. In other embodiments, the second elastomeric material is a combination of the first elastomeric material and another material. In some embodiments, the second elastomeric material is a composite elastomeric material.

[0073] The properties of the second elastomeric material are different from the properties of the first elastomeric material. For example, the second elastomeric material is more elastic than the first elastomeric material. In addition, the viscoelastic properties of the second elastomeric material are different from the viscoelastic properties of the first elastomeric material such that the second elastomeric material is less viscous than the second elastomeric material. Thus, the energy required to deform the first elastomeric material is greater than the energy required to deform the second elastomeric material (i.e., the deformation energy of the first elastomer is greater than the deformation energy of the second elastomeric material).

[0074] The viscoelastic properties of a viscoelastic material can be determined using the following equation:

number

[0075] Thus, because the second elastomeric material is less viscous than the first elastomeric material, the magnitude of the tan(δ) parameter of the second elastomeric material is less than the magnitude of the tan(δ) parameter of the first elastomeric material.

[0076] If the flexibility zone 112 is not made of the second elastomeric material, the track 100 is made of more of the first elastomeric material. In other words, the second elastomeric material replaces the first elastomeric material in the flexibility zone 112. This may help reduce the energy dissipated by the track 100, as described below.

[0077] As described in more detail below, the presence of the flexibility zone 112, along with the features described above, can assist in reducing the energy dissipated by the track 100 when the track 100 is being deformed. In some cases, the presence of the flexibility zone 112 can help reduce the energy dissipated in the inter-lug sections 110.

[0078] In operation, as the axle to which the sprocket wheel assembly 60 is operatively connected rotates, the sprocket wheel assembly 60 also rotates, thereby engaging and thus driving the track 100. More precisely, the recesses 62 of the sprocket wheel assembly 60 engage the lugs 108 of the track 100. Due to the transmission of forces and motion, the track 100 is subjected to relatively high stresses at the lugs 108 and within the carcass 102. In some cases, the stresses may be high at the root of the lugs 108. In general, the sprocket wheel assembly 60 and the track 100 are configured such that the radial surface of the sprocket wheel assembly 60 does not engage the inner surface 102 of the track 100 between the lugs 108 (i.e., the sprocket wheel assembly 60 does not apply shear or compressive forces in the inter-lug sections 110). In some cases, the radial surface of the sprocket wheel assembly 60 may contact the track 100 in the inter-lug sections 110. In such case, the protective layer 140 of each inter-lug section 110 is configured to initially engage the radial surface of the sprocket wheel assembly 60 and thus protect its corresponding flexible zone 112 as well as the inner surface 102 from premature wear.

[0079] During operation, the track system 50 experiences rolling resistance. Thus, there is energy loss in the track system 50. The endless track 100 contributes to the rolling resistance of the track system 50. For example, the bending resistance of the endless track 100 may contribute to the rolling resistance of the track system 50. A portion of the rolling resistance, and therefore the energy dissipated by the endless track 100, is due to hysteresis in the endless track 100.

[0080] Because the lugs 108 and carcass 102 are made of a first elastomeric material that has a higher hysteresis than the second elastomeric material, the lugs 108 and carcass 102 dissipate more energy when deformed than the flexible zones 112. The first elastomeric material is used despite being a source of energy dissipation because it is configured to withstand the high stresses to which the lugs 108 and carcass 102 are subjected. In other words, the first elastomeric material is configured to at least partially prevent or reduce tearing or damage to the lugs 108 and carcass 102 caused by high stresses. In some embodiments, the properties of the first elastomeric material that exacerbate energy dissipation also help prevent or reduce tearing or damage to the lugs 108 and carcass 102.

[0081] The flexible zones 112 are made of a second elastomeric material that has a lower hysteresis than the first elastomeric material, such that each of the flexible zones 112 is configured to dissipate less energy than a correspondingly sized zone of the carcass 102. The flexible zones 112 are present and made of a second elastomeric material because the stresses in the flexible zones 112 are generally not as high as the stresses in the lugs 108 and carcass 102. Thus, a second elastomeric material may be used that is configured to elastically deform more easily than the first elastomeric material, dissipate less energy than the first elastomeric material, but provide less protection against tears and damage than the first elastomeric material.

[0082] Thus, the presence of the flexibility zone 112 can reduce the rolling resistance of the track system 50 and can reduce the energy dissipated by the track 100 because the energy required to deform the track 100 (i.e., a track having the flexibility zone 112 (i.e., the deformation energy)) is less than the energy required to deform a track without the flexibility zone 112. In some embodiments, the presence of the flexibility zone 112 can reduce the rolling resistance of the track 100 by about 5%, about 6%, or about 7%. In other embodiments, the presence of the flexibility zone 112 can reduce the rolling resistance of the track 100 by about 4%, about 3%, or about 2%. In some cases, the presence of the flexibility zone 112 is such that the rolling resistance of the track 100 is less than about 70 Nm when the overall temperature within the track 100 is about 40° C.

[0083] In some embodiments, the presence of the flexibility zone 112 can reduce the energy dissipated by the track 100 by at least about 5%. In other embodiments, the presence of the flexibility zone 112 can reduce the energy dissipated by the track 100 by at least about 7%. In other embodiments, the presence of the flexibility zone 112 can reduce the energy dissipated by the track 100 by at least about 10%.

[0084] A method for manufacturing the track 100 will now be described.

[0085] The carcass 102 having the lugs 108 is formed using methods known in the art. For example, the carcass 102 and lugs 108 may be molded and then cured to shape. The carcass 102 and lugs 108 are made of a first elastomeric material.

[0086] The method also includes forming a flexible zone 112 with a second elastomeric material.

[0087] In some embodiments, the flexibility zone 112 is formed into an already formed and / or already in use track. In such embodiments, it is contemplated that a portion of the first elastomeric material between the lugs 108 is removed to accommodate the flexibility zone 112, and a second elastomeric material is disposed between the lugs 108 and then cured, thus forming the flexibility zone 112.

[0088] The various components of the track system 50 are made of conventional materials (e.g., in most cases metals and metal alloys, such as steel) by conventional manufacturing processes (e.g., casting, molding, etc.). The present technique does not require any particular materials or manufacturing methods. The present technique requires only that each component be suitable for the purpose for which it is intended and the application for which it is to be used. Any material or manufacturing method that produces such components can be used with the present technique.

[0089] Modifications and improvements to the above-described embodiments of the technology may become apparent to those skilled in the art. The foregoing description is intended to be illustrative and not limiting. Accordingly, the scope of the technology is intended to be limited only by the appended claims. [Explanation of symbols]

[0090] 40 Harvester 42 Frames 44 Engine 46 Rear wheel 50 Track System 60 Sprocket wheel assembly 62 Recess 70 frames 72 Main frame member 74 Preceding frame member 76 Subsequent frame member 80 Front idler wheel assembly 82 Rear idler wheel assembly 84a Support Wheel Assembly 84b Support Wheel Assembly 84c Support Wheel Assembly 86 Tandem 100 Tracks 102 Carcass, inner surface 104 Inside 106 Exterior 108 Rug 110 Interlug Section 112 Flexibility Zone 114 Reinforcement Cable 116 Reinforcement sheet 120a wheel engaging section, wheel engaging portion 120b wheel engaging section, wheel engaging portion 124 Ridge 126 Tread 130 Preceding part 132 Middle part 134 Subsequent Part 140 Protective layer T Thickness T1 Thickness T2 Thickness T3 Thickness

Claims

1. 1. An elastomeric endless track for a track system, the endless track comprising: a carcass having an inner surface engageable by at least one wheel assembly and an outer surface engageable with a ground surface, the carcass being made of at least a first elastomeric material; a plurality of longitudinally spaced lugs projecting from the inner surface, the plurality of longitudinally spaced lugs defining a plurality of inter-lug sections located between adjacent longitudinally spaced lugs; Equipped with at least some of the plurality of inter-lug sections include a zone made of at least a second elastomeric material; Elastomer tracks.

2. The elastomeric track of claim 1 , wherein the second elastomeric material is less viscous than the first elastomeric material.

3. 10. The elastomeric endless track of claim 1, wherein each zone of the plurality of inter-lug sections extends longitudinally from a bottom portion of a first lug to a bottom portion of a second lug adjacent the first lug.

4. 10. The elastomeric endless track of claim 1, wherein a width of each zone of the plurality of inter-lug sections is the same as a width of the plurality of longitudinally spaced lugs.

5. The elastomeric endless track of claim 1 , wherein a width of each zone of the plurality of inter-lug sections spans at least 50% of a width of the carcass.

6. 2. The elastomeric endless track of claim 1, wherein the inner surface defines a first wheel-engaging portion on a first side of the plurality of longitudinally spaced lugs and a second wheel-engaging portion on a second side of the plurality of longitudinally spaced lugs, each zone of the plurality of inter-lug sections extending from the first wheel-engaging portion to the second wheel-engaging portion.

7. each zone of the plurality of inter-lug sections has a leading portion, an intermediate portion, and a trailing portion; the leading portion having a first thickness, the intermediate portion having a second thickness, and the trailing portion having a third thickness; the first and third thicknesses are smaller than the second thickness; 10. The elastomeric endless track of claim 1.

8. 8. The elastomeric endless track of claim 7, wherein the intermediate portion of each zone of the plurality of inter-lug sections is approximately at a center of the inter-lug section.

9. 8. The elastomeric endless track of claim 7, wherein the intermediate portion of each zone of the plurality of inter-lug sections is offset from a center of the inter-lug section.

10. 2. The elastomeric endless track of claim 1, wherein each zone of the plurality of inter-lug sections has a leading portion, a middle portion, and a trailing portion, the leading portion having a first thickness, the middle portion having a second thickness, and the trailing portion having a third thickness, and the first, second, and third thicknesses are the same.

11. 10. The elastomeric track of claim 1, wherein a ratio of a thickness of the second elastomeric material to a thickness of the first elastomeric material in some of the inter-lug sections is at least about 5%.

12. The elastomeric endless track of claim 1 , wherein each zone of the plurality of inter-lug sections has a protective layer, the protective layer being made of a third material.

13. 13. The elastomeric track of claim 12, wherein the third material is the same as the first elastomeric material.

14. 10. The elastomeric track of claim 1, wherein a first deformation energy of the first elastomeric material is greater than a second deformation energy of the second elastomeric material.

15. 10. The elastomeric track of claim 1, wherein the first elastomeric material dissipates more heat than the second elastomeric material upon deformation of the first and second elastomeric materials.

16. 10. The elastomeric endless track of claim 1, wherein upon deformation of the endless track, each zone of the plurality of inter-lug sections dissipates less energy than a correspondingly sized zone of the carcass.

17. 10. The elastomeric track of claim 1, wherein the presence of the plurality of inter-lug sections reduces the rolling resistance of the track by about 5%.

18. 18. The elastomeric track of claim 17, wherein the rolling resistance of the track is less than about 70 Nm when the temperature within the track is about 40°C.

19. the first elastomeric material has a first storage modulus to loss modulus ratio; the second elastomeric material has a second storage modulus to loss modulus ratio; the first storage modulus to loss modulus ratio is greater than the second storage modulus to loss modulus ratio; 10. The elastomeric endless track of claim 1.

20. 20. The elastomeric endless track of claim 19, wherein the track system has a rolling resistance and the at least some of the inter-lug sections are configured to dissipate less deformation energy than a remainder of the carcass, thereby reducing the rolling resistance.

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