Tandem wheel assembly with wheel end adjustment

Abstract

A tandem wheel assembly for a work vehicle includes a tandem wheel housing having a central opening disposed about a pivot axis and first and second wheel end openings disposed about associated first and second wheel axes substantially parallel to the pivot axis. A center sprocket within the tandem wheel housing is rotatable about the pivot axis. The first and second wheel end assemblies include first and second wheel end shafts, sprockets, and a housing. The first and second wheel end sprockets are mounted to associated shafts and aligned so that the center sprockets engage at least one chain that transmits rotation of the center sprocket about the pivot axis to rotate the first and second wheel end sprockets about the first and second wheel axes. The first and second wheel end housings support the first and second wheel end shafts for relative rotation about the first and second wheel axles. The first wheel end housing is adjustably mounted to the tandem wheel housing to vary a first distance between the pivot axis and the first wheel axis.

Description

Technical Field

[0001] The present disclosure generally relates to a tandem wheel assembly for a work vehicle. Background Art

[0002] For example, the work vehicles used in construction, agriculture, forestry, mining and other industries can utilize tandem wheel assemblies (also referred to as bogie axles) to support the heavy loads of four or more ground-engaging wheels or track wheels that utilize a single wheel axle, and the single wheel axle allows the wheels to pivot together to maintain ground contact above the changing terrain without significantly shifting other areas of the work vehicle, including the operator's cabin and work tools (e.g., blades). Such tandem wheel assemblies can also be driven (e.g., driven from the work vehicle drivetrain by a transmission, or can be powered by themselves). A work vehicle that often utilizes tandem wheel assemblies is a motor grader. Applications may require a motor grader to deliver high torque, low speed power to the wheels or tracks that engage the ground, which is accomplished by performing a high ratio gear reduction on the wheels. Different applications may be suitable for different motor graders with different load-bearing capacities. Various machines may have different overall dimensions and use tandem wheel assemblies of different sizes and wheelbases. Summary of the Invention

[0003] The present disclosure provides a tandem wheel assembly for a work vehicle in which the fore-aft spacing from the pivot axis of one or more of the wheel ends can be adjusted.

[0004] In one aspect, the present disclosure provides a tandem wheel assembly for a work vehicle. The tandem wheel housing has a central opening disposed about a pivot axis and first and second wheel end openings disposed about associated first and second wheel axes substantially parallel to the pivot axis. A center sprocket within the tandem wheel housing is rotatable about the pivot axis. The first and second wheel end assemblies include first and second wheel end shafts, sprockets, and a housing. The first and second wheel end shafts extend through the associated first and second wheel end openings of the tandem wheel housing. The first and second wheel end sprockets are mounted to the associated first and second wheel end shafts and aligned within the tandem wheel housing to engage the center sprockets via at least one chain, which transmits rotation of the center sprocket about the pivot axis, thereby rotating the first and second wheel end sprockets about the associated first and second wheel axes. The first and second wheel end housings support the first and second wheel end shafts for relative rotation about the associated first and second wheel axes. The first wheel end housing is adjustably mounted to the tandem wheel housing to vary a first distance between the pivot axis and the first wheel axis.

[0005] In another aspect, the present disclosure provides a tandem wheel assembly for a work vehicle. The tandem wheel housing has a central opening disposed about a pivot axis and first and second wheel end openings disposed about associated first and second wheel axes substantially parallel to the pivot axis. A center sprocket within the tandem wheel housing is rotatable about the pivot axis. The first and second wheel end assemblies include first and second wheel end shafts, sprockets, and a housing. The first and second wheel end shafts extend through the associated first and second wheel end openings of the tandem wheel housing. The first and second wheel end sprockets are mounted to the associated first and second wheel end shafts and aligned within the tandem wheel housing to engage the center sprockets via at least one chain, which transmits rotation of the center sprocket about the pivot axis, thereby rotating the first and second wheel end sprockets about the associated first and second wheel axes. The first and second wheel end housings support the first and second wheel end shafts for relative rotation about the associated first and second wheel axes. One or more of the first and second wheel end housings are adjustably mounted to the tandem wheel housing to vary one or more of the first and second distances between the pivot axis and the associated first and second wheel axes.

[0006] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a simplified perspective illustration of an exemplary work vehicle in the form of a motor grader in which a tandem wheel assembly may be used in accordance with the present disclosure;

[0008] Figure 2 is an isometric view of an exemplary tandem wheel assembly for an exemplary motor grader;

[0009] Figure 3 is used for Figure 2 an isometric view of an exterior side of an exemplary housing arrangement of an exemplary tandem wheel assembly;

[0010] Figure 4 is an isometric view of its interior side;

[0011] Figure 5 is a side elevation view of an exemplary tandem wheel housing of a tandem wheel assembly;

[0012] Figure 6 is a side elevational view of an exemplary wheel end housing of an exemplary tandem wheel assembly;

[0013] Figure 7 It is from Figure 2 A top cross-sectional view of an exemplary tandem wheel assembly taken along plane 7-7;

[0014] Figure 8 It shows that Figure 5 The train wheel housing and Figure 6 An enlarged partial cross-sectional view of an exemplary wheel end of a wheel end housing;

[0015] Figure 9 is a side elevation view showing an exemplary wheel end housing in a first position;

[0016] Figure 10 is a side elevation view showing an exemplary wheel end housing in a second position;

[0017] Figure 11 is a side elevation view of another exemplary tandem wheel housing of a tandem wheel assembly;

[0018] Figure 12 is a side elevational view of another exemplary wheel end housing; and

[0019] Figure 13 It shows that Figure 11 The train wheel housing and Figure 12 An enlarged partial cross-sectional view of another exemplary wheel end of a wheel end housing.

[0020] Like reference numbers in the various drawings indicate like elements. DETAILED DESCRIPTION

[0021] One or more exemplary embodiments of the disclosed tandem wheel assembly are described below, as illustrated in the accompanying drawings of the drawings briefly described above. Various modifications to the exemplary embodiments may be anticipated by those skilled in the art.

[0022] As used herein, unless otherwise limited or modified, a list having elements separated by conjunction terms (e.g., "and") and also preceded by the phrase "one or more of" or "at least one of" indicates a configuration or arrangement that potentially includes the individual elements of the list or any combination thereof. For example, "at least one of A, B, and C" or "one or more of A, B, and C" indicates the possibility of only A, only B, only C, or any combination of two or more of A, B, and C (e.g., A and B; B and C; A and C; or A, B, and C).

[0023] Additionally, in describing the present disclosure in detail, directional and orientation terms, such as "longitudinal," "inner," "outer," "radial," "axial," "circumferential," "lateral," and "transverse," may be used. Such terms are defined, at least in part, relative to a wheel axle, a pivot axis, and / or a work vehicle. As used herein, the term "longitudinal" indicates an orientation along the length of the device; the term "lateral" indicates an orientation along the width of the device and orthogonal to the longitudinal orientation; and the term "transverse" indicates an orientation along the height of the device and orthogonal to the longitudinal and transverse orientations. These orientations may be defined relative to a work vehicle or a direction of travel of a work vehicle to which a component may be attached. In other examples, the components to which those terms refer may be reversed in accordance with the present disclosure.

[0024] Overview

[0025] A work vehicle (e.g., a motor grader) typically includes components such as a chassis, a powertrain (e.g., an engine and drivetrain), a suspension, and a work implement (e.g., a blade) to perform tasks on various terrains and conditions. Typically, a work vehicle may perform tasks that require consistent work implement positioning (e.g., a blade scraping a work area at a desired height to produce a flat surface). The wheel axle area may support significant static weight loads from onboard components (e.g., engine, transmission, axles, work implements, etc.) and encounter significant operational loads (e.g., shocks / loads via attached work implements and through the wheels and suspension). Therefore, the work vehicle must adapt to the changing terrain, static loads, and operational loads resulting from the work task while maintaining the desired implement positioning. The tandem wheel assembly can adapt to such load or grade changes by mounting the wheel assemblies (typically the rear wheel assemblies) together to pivot relative to the work vehicle, thereby providing ground contact for the wheels without significantly hindering work implement placement.

[0026] In the case of a motor grader, the work implement is typically a large blade that cuts and moves large amounts of ground during the initial stages of site preparation. During the final stages, the final base surface must be flat and precisely sloped over large areas and / or distances (e.g., several miles of road) even after the rear wheels have trailed behind the blade. Motor graders must travel at sufficient speed to be productive while preventing unwanted bounce and sway; for example, motor graders can operate at speeds ranging from a slow "crawl" (e.g., 0.3 to 7 miles per hour (mph)) to higher speeds (e.g., 40 mph or more during transport and other operating conditions). During use, the blade experiences resistance, such as friction from the ground, the weight of previously loosened soil and debris material as it flows along the blade, and impact loads from obstacles. The large blade size of modern motor graders carries a significant volume of ground or other material. The corresponding operating loads are transmitted through the chassis and drivetrain to the vehicle wheels, which transfer the load to the surface being prepared. Thus, the drivetrain and wheels can aid site preparation performance by maintaining ground contact for consistent traction while also distributing the load evenly across the ground surface to minimize stress on the scraped work surface.

[0027] The present disclosure provides a tandem wheel assembly with a tandem wheel housing that allows different components to be set therein to provide wheelbases of various lengths for work vehicles. Only a single tandem wheel housing needs to be manufactured to accommodate wheelbases of different lengths. Work vehicle manufacturers can provide a series of vehicle platforms of different models or categories, wherein multiple similar work vehicles vary in certain aspects (e.g., chassis size, engine size, or various other features). For example, a motor grader can be provided in different models with different blade sizes and different desired operating loads, which may require different wheel sizes, engine sizes, wheelbases, and the like. In some examples, related models can have tandem wheelbases that vary from approximately 60mm to 160mm (e.g., wheelbases of 1480mm, 1540mm, and 1640mm). However, these different models also have many shared features and components (e.g., drivetrain components, engine size, etc.). Tandem wheel assemblies for work vehicles of different models may require significant redesign and variations in individual components across platform lines (e.g., chain size and / or length, sprocket size, and number of teeth). Such tandem wheel assemblies may have complex, multi-part tandem wheel housings with several major components sized for each different model size. The present disclosure provides a single tandem wheel housing that allows for various fore-aft adjustments of the wheel end assembly, and thereby various adjustments of the wheelbase of the tandem wheel assembly.

[0028] In certain embodiments, the tandem wheel assembly has an adjustment feature that allows the wheel end assembly of the tandem wheel assembly to move (e.g., slide or translate) substantially in the front-to-back direction or travel direction of the work vehicle for initial installation in the factory or for subsequent on-site adjustment. The adjustment feature may include one or more adjustment openings for connecting the wheel end assembly to the tandem wheel housing of the tandem wheel assembly. Such an adjustment opening may include multiple holes or slots in either or both of the outer walls of the wheel end assembly (e.g., at its mounting flange) and the tandem wheel housing. The slots may be oriented so that their long dimensions are substantially aligned with the front-to-back direction or travel direction of the work vehicle so that the wheel end assembly can be positioned in various front-to-back positions relative to the tandem wheel housing. Once positioned, a bolt or other threaded or unthreaded pin-type structure may be received in the slot to clamp the wheel end assembly to the tandem wheel housing and thereby removably fix the relative position of the wheel end assembly. As described, the slots may be formed in two mating components (i.e., the wheel end assembly and the tandem wheel housing) to extend the front-to-back adjustment distance. Instead of or in addition to the slots, a plurality of redundant openings (i.e., circular holes) spaced apart in the fore-aft direction may be included in either or both mating components to provide for adjustable mounting of the wheel end assemblies. While providing adjustability of both wheel end assemblies may be advantageous, the present disclosure also contemplates that only one of the wheel end assemblies (e.g., the front or rear wheel end assembly) in a tandem wheel assembly may be adjustable, while the other may be in a fixed relative position.

[0029] Furthermore, the adjustment features of the tandem wheel assemblies disclosed herein may include one or more tensioning mechanisms for applying a mechanical advantage to move the wheel end assemblies relative to the tandem wheel housing. In some embodiments, such a tensioning mechanism may be in the form of a jackscrew tensioner operably mounted between one or both of the wheel end assemblies and the tandem wheel housing. For example, the tensioning mechanism may include a bracket secured to the tandem wheel housing and a bracket secured to each (or associated) wheel end assembly. The bracket may include openings for bolts or other pin structures for coupling the brackets together and allowing adjustment of the fore-aft spacing between the brackets. One or both openings in the bracket may be threaded, and the bolt may engage the threaded openings such that rotation of the bolt in either clockwise direction causes the brackets to move relatively closer or further apart. In one example, one or more brackets on the tandem wheel housing are fixed in place, and the wheel end assemblies are moved forward or rearward by the tensioning mechanism. An alternative tensioning mechanism may include an unthreaded opening in the bracket and a separate threaded nut for threadedly engaging the bolt. In still other cases, a bracket may not be required, and integral features of the tandem wheel housing and wheel end assembly may define an opening or threaded opening that engages a pin connector (e.g., a bolt). Other tensioning mechanisms, including variable links, that may be manually or powered (e.g., electrically or hydraulically powered) are contemplated.

[0030] In certain embodiments, the operating elements of the tandem wheel assembly are partially or completely flooded with lubricating and cooling oil. The tandem wheel assembly of the present disclosure can operate in such a "wet" environment by employing sliding face seals between the tandem wheel housing and the wheel end assembly. The face seal can be an O-ring or other gasket that extends around the opening in the tandem wheel housing for the wheel end. The face seal also extends around the adjustment opening (e.g., a slot and / or hole) to contain the oil passing between the tandem wheel housing / wheel end interface. The face seal can be captured in a corresponding recess or groove in the tandem wheel housing or the wheel end assembly. When the wheel end assembly is adjusted, the face seals move with their main components and slide sealingly against the face surface of the mating component, for example, against the outer wall of the tandem wheel housing if the face seal is mounted to the wheel end assembly, or against the inside surface of the mounting flange of the wheel end assembly if the face seal is mounted to the tandem wheel housing. In such "wet" applications, adjustment features may be limited to slots or openings located within the area circumscribed by the face seal(s) and otherwise closed by corresponding structure (e.g., surfaces of mating structures, mechanical fasteners, and the like). This limitation does not apply to "dry" applications, such that slots and redundant openings that allow adjustment may not be sealed.

[0031] One or more exemplary embodiments of the disclosed tandem wheel housing are described below. While the discussion herein may sometimes focus on exemplary applications of tandem wheel assemblies for motor graders, the disclosed tandem wheel assemblies may also be applied to bogie axles or tandem axles in other types of work vehicles, including self-propelled or towed work vehicles and various other agricultural machines (e.g., articulated tractors, utility tractors, front-end loaders, harvesters, and the like), various construction and forestry machines (e.g., forwarders, skidders, etc.), and transport vehicles (e.g., semi-trailers).

[0032] Exemplary embodiments of tandem wheel assemblies

[0033] refer to Figure 1 In some embodiments, the disclosed work vehicle 10 may be a motor grader, although, as noted, the tandem wheel assembly described herein may be applied to a variety of machines, such as other construction vehicles, agricultural vehicles including articulated frame tractors, forestry vehicles (e.g., forwarders), and transport vehicles (e.g., semi-trailers). As shown, work vehicle 10 may be considered to include a chassis 12 comprised of a rear frame 14 and a front frame 16 for carrying a blade 18 selectively positioned by an implement drive system 20. Work vehicle 10 may further be considered to include a powertrain 24, an operator cab 26, a control system 28, and a hydraulic system 30. In the illustrated example, work vehicle 10 includes a tandem wheel assembly 32 on rear frame 14 for mounting two wheels 36, 38 on the left side of work vehicle 10 and two wheels 42, 44 on the right side of work vehicle 10. Each wheel 36, 38, 42, 44 is mounted to tandem wheel assembly 32 via its wheel hub 46. The wheels 36, 38, 42, 44 include a pair of left wheels defined by a first left wheel 36 and a second left wheel 38, and a pair of right wheels defined by a first right wheel 42 and a second right wheel 44 (also collectively referred to as the "four tandem wheels 36, 38, 42, 44"). A third set of wheels 48 is mounted on the front axle (not shown) on the front frame 16, and the third set of wheels 48 can be configured to be automatically steerable or can be steered by the operator. It should be noted that any left / right wheel pair can be arranged for each left / right lateral side of the work vehicle 10 (e.g., on the left and right sides). Figure 1 Dual wheels on the side in the x-direction as shown in FIG.

[0034] Typically, powertrain 24 includes a propulsion source (e.g., engine 50) that supplies power to work vehicle 10, either directly as mechanical power or after being converted to electric power (e.g., via a battery) or hydraulic power. In one example, engine 50 is an internal combustion engine, such as a diesel engine, controlled by an engine control module (not shown) of control system 28. It should be noted that the use of an internal combustion engine is merely an example, as the propulsion source may be a fuel cell, an electric motor, a hybrid gas-electric motor, or other power-generating device. A transmission 52 transfers power from engine 50 to one or more of wheels 36, 38, 42, 44 of tandem wheel assembly 32. In addition, powertrain 24 includes wheel steering components 54, which include various devices (e.g., a power steering pump and circuitry, a steering mechanism, and the like) that couple manual (e.g., operator steering controls or wheels) and / or automatic (via control system 28) steering input to one or more of the set of wheels (e.g., third set of wheels 48).

[0035] In addition to providing tractive power to propel work vehicle 10, engine 50 can also power various onboard subsystems, including various electrical and hydraulic components of the work vehicle, and provide off-board power to other subsystems remote from work vehicle 10. For example, engine 50 can provide mechanical power that is converted to an electrical format to operate the electronics of control system 28 and one or more electric drives of work vehicle 10. Thus, powertrain 24 can have mechanical-to-electrical conversion components 56, one or more batteries 58, and associated electronics, including various alternators, generators, voltage regulators, rectifiers, inverters, and the like. Engine 50 can also provide mechanical power that is converted to a hydraulic format to power various pumps and compressors that pressurize fluid to drive various actuators of hydraulic system 30 to power wheel steering and braking, as well as various work implements, on work vehicle 10. The hydraulic system 30 may include other components (e.g., valves, flow lines, pistons / cylinders, seals / gaskets, etc.) so that control of various devices can be affected by and based on hydraulic, mechanical, or other signals and movements.

[0036] Control system 28 may be configured as a computing device with an associated processor device and memory architecture, as a hardwired computing circuit (or circuits), as a programmable circuit, or as a hydraulic, electric, or electro-hydraulic controller. Control system 28 may be configured to perform various computations and control functions with respect to work vehicle 10, including various devices associated with powertrain 24, hydraulic system 30, implement drive system 20, and various additional components of work vehicle 10. In some embodiments, control system 28 may be configured to receive input signals in various formats (e.g., as hydraulic signals, voltage signals, current signals, etc.) and output command signals in various formats (e.g., as hydraulic signals, voltage signals, current signals, mechanical movements, etc.).

[0037] As described above, the hydraulic system 30 can be controlled by the control system 28 (automatically, via operator input, or both). The hydraulic system 30 can be powered by the engine 50 and configured in various arrangements to serve multiple hydraulic functions (e.g., powering the implement drive system 20). Thus, the hydraulic system 30 can have components (not shown) including a pump for supplying pressurized hydraulic fluid, a reservoir for storing hydraulic fluid, and various valves (e.g., control valves) associated with each function.

[0038] In the illustrated example, when the work vehicle 10 is driven in the forward direction (in Figure 1 18 and supports the majority of the weight on the rear frame 14. The tandem wheel assembly 32 is pivotable about a pivot axis 60. Specifically, each of the pair of left wheels 36, 38 and the pair of right wheels 42, 44 can independently pivot about the pivot axis 60 relative to the work vehicle 10. During use, if the work vehicle 10 encounters an obstacle or uneven surface, the tandem wheel assembly 32 accommodates this by pivoting. Thus, the transmission of bumps or changes in terrain is reduced or eliminated, maintaining the blade 18 and cabin 26 in a relatively stable position that maintains traction and weight distribution. Likewise, the four tandem wheels 36, 38, 42, 44 maintain ground contact while pivoting.

[0039] Tandem wheel assembly 32 mounts four tandem wheels 36, 38, 42, 44 below rear frame 14. Exemplary tandem wheel assembly 32 may include a differential housing 62, a first mounting arm 64, a second mounting arm 66, a first pivot joint 68, a second pivot joint 70, and first and second tandem wheel housings 72. Tandem wheel assembly 32 also functions to allow the four tandem wheels 36, 38, 42, 44 to pivot relative to work vehicle 10 about pivot axis 60. Differential housing 62 is rigidly attached to first and second mounting arms 64, 66, which are secured to chassis 12 of work vehicle 10 (e.g., via bolts extending through arm apertures 88). Thus, differential housing 62 is relatively fixed in position, and one or both of first and second tandem wheel housings 72 independently pivot relative to differential housing 62 via first and second pivot joints 68, 70. It will be appreciated that tandem wheel assembly 32 provides a robust and elegant design.

[0040] As also described above, the tandem wheel assembly 32 includes components of the drivetrain 24 to transmit motive force to each of the four wheels 36, 38, 42, and 44. A differential 100 is mounted in the differential housing 62 and connected to a drive shaft 102 driven by the transmission 52. The differential 100 includes gearing components to separate and translate the rotation of the drive shaft 102 laterally outward toward the first and second tandem wheel housings 72. Pinion gears 104 at the ends of the drive shaft 102 mesh with a differential ring gear 106 mounted with a differential case 108, which is coupled (via side gears 114) to a first inboard shaft 110 and a second inboard shaft 112. The differential 100 may be a limited-slip differential having a clutch assembly 115 to prevent slip. The first inboard shaft 110 is coupled to a first outboard shaft 116 after a gear reduction provided by a planetary gear set 118. Similarly, the second inner shaft 112 is coupled to the second outer shaft 117 after a gear reduction provided by planetary gear sets 118 and 119. Specifically, the planetary gear set 118 (and similarly for the planetary gear set 119) includes a sun gear 120 formed on (or mounted on) the first inner shaft 110, a plurality of planet gears 122 within a fixed annular gear 124, and a carrier 126 that rotates with the plurality of planet gears 122. Each carrier 126 is non-rotatably attached to the outer shafts 116 and 117, respectively, extending into the first and second train wheel housings 72. Each planetary gear set 118 and 119 is selectively activated by a clutch assembly 128.

[0041] The components of the drivetrain 24 in the tandem wheel assembly 32 may include additional support components, such as bearings for any rotating components. For example, the drive shaft 102 is supported in the differential housing 62 by first and second bearings 130a, 130b. The first and second bearings 130a, 130b may be tapered roller bearings mounted in opposing tapered orientations to accommodate axial loads in addition to rotation. The first inboard shaft 110 may be supported by one or more rotating bearings. As shown, tapered roller bearing 132 supports the first inboard shaft 110 between the differential 100 and the planetary gear set 118. The first outboard shaft 116 may be supported in the fixed pivot portion 90 by first and second bearings 134a, 134b. The first and second bearings 134a, 134b may also be opposing tapered roller bearings. The second inboard shaft 112 and the second outboard shaft 117 may be similarly arranged.

[0042] Now refer to Figure 3 and Figure 4 Each tandem wheel housing 72 may be a generally hollow section having an inner wall 160 and an outer wall 162 defining an interior volume 164 that extends from a front wall 166 to a rear wall 168 and between an upper wall 170 and a lower wall 172. A longitudinal axis 173 of the tandem wheel housing 72 is defined between the front wall 166 and the rear wall 168 and is perpendicular to the pivot axis 60. The tandem wheel housing 72 may be formed from cast metal or other suitable structural material.

[0043] Each tandem wheel housing 72 includes a pivot portion 82 extending laterally inwardly toward the differential housing 62. The pivot portion 82 is rotatably journaled on a fixed pivot portion 90 that is non-rotatably mounted relative to the differential housing 62 (and therefore fixed relative to the chassis 12 of the work vehicle 10). The inner wall 160 includes the pivot portion 82 as an integral part of the tandem wheel housing 72 (e.g., integrally formed simultaneously from the same material using the same process), although in other examples, the pivot portion 82 may be a separate piece. The integral construction of the pivot portion 82 with the tandem wheel housing 72 can advantageously reduce parts and assembly time, thereby reducing manufacturing costs, while also providing suitable strength and rigidity to accommodate internal and external loads on the tandem wheel housing 72. The pivot portion 82 defines a central opening 83 in the inner wall 160 that is disposed about the pivot axis 60 and communicates with the interior volume 164.

[0044] One or more rotation limits 92 may be provided on the tandem wheel housing 72 to define the maximum pivot travel of the tandem wheel housing 72 (e.g., by contacting a lower portion of the chassis 12). It will be appreciated that the fixed pivot portion 90 is fixed relative to the work vehicle 10 while supporting the pivot portion 82 for journal rotation at the exterior of the fixed pivot portion 90 and also supporting the outboard shaft 116 for power transfer rotation. Although not shown in detail, the differential housing 62 may house additional components of the differential 100, including brakes, u-joint(s), ring gears, pinion shaft(s), pinion(s), planetary gear(s), side gears, clutch plates, bearings, and the like. Any type of differential may be implemented within the tandem wheel assembly 32, including an open differential, a limited slip differential, or the like. The differential housing 62 also mounts portions of the drive shaft 102 ( Figure 7 ) and portions of the first inner shaft 110 and the second inner shaft 112.

[0045] The components in each tandem wheel housing 72 can be identical mirror images. Each tandem wheel housing 72 includes a center sprocket 140 mounted for common rotation with the first outboard shaft 116, a first chain 142 connecting the center sprocket 140 to a front wheel end assembly 234, or first wheel end assembly 234, on a first side of the center sprocket 140, and a second chain 146 connecting the center sprocket 140 to a rear wheel end assembly 236, or second wheel end assembly 236, on a second side of the center sprocket 140. In some embodiments, the center sprocket 140 is a double-loop sprocket to which the first chain 142 extending to the first wheel end assembly 234 and the second chain 146 extending to the second wheel end assembly 236 are mounted. Each wheel end assembly 234, 236 includes a wheel end sprocket 238, a wheel end axle 240 supporting the corresponding wheel 36, 38, 42, 44, and a wheel end housing 242. Each wheel end assembly 234, 236 is movable in a fore-and-aft direction relative to the center sprocket 140.

[0046] The wheel end sprocket 238 of the wheel end assembly 234 is aligned with one of the two loops of the center sprocket 140 and is thereby connected by the first chain 142. The wheel end sprocket 238 of the wheel end assembly 236 is aligned with the other of the two loops of the center sprocket 140 and is thereby connected by the second chain 146. Although the first chain 142 is shown mounted inboard relative to the second chain 146, these relative positions can be reversed. The wheel end sprockets 238 will have equal dimensions (e.g., equal numbers of teeth) to drive the corresponding first and second left wheels 36, 38 at substantially equal speeds. The first and second chains 142, 146 can be leaf chains, roller chains, or other suitable drive chains for heavy construction applications. The chains 142, 146 can be continuous chains without detachable links or "master" links to improve the torque handling capabilities of the chains 142, 146.

[0047] Wheel end axles 240 are mounted on their wheel end sprockets 238 for common rotation therewith. Each wheel end axle 240 extends through an opening 244 in the outer wall 162 and extends laterally outward from the outer wall 162. Each opening 244 has a diameter greater than the diameter of the wheel end axle 240, and a center 245 is defined at the center point of the opening 244. Each wheel end axle 240 supports the hub 46 of the corresponding wheel 36, 38, 42, 44 at its end for common rotation therewith.

[0048] Each wheel end housing 242 extends laterally outward from the outer wall 162. Each wheel end housing 242 includes a mounting flange 246 having an inwardly facing surface 246a that is parallel to and disposed against the outer wall 162, and an axle mounting portion 248 that extends laterally outward from the mounting flange 246. The axle mounting portion 248 has a wheel end opening 250 at its end that supports at least a portion of the wheel hub 46. The axle mounting portion 248 can be conical in shape. The wheel end axle 240 extends through the wheel end housing 242 and the wheel end opening 250, and the wheel end axle 240 and the wheel hub 46 are supported in the wheel end housing 242 via a swivel bearing (not shown). The wheel end housing 242 may mount various additional support components (not shown), such as roller bearings, and, as described above, may mount gear components (not shown, such as a planetary gear set) for providing additional gear reduction between the wheel end sprocket 238 and the wheel hub 46. An access panel 252 may be provided in the interior wall 160 for allowing assembly access / maintenance access to the wheel end sprocket 238 or other components within the tandem wheel housing 72.

[0049] The wheel end shaft 240 of the first wheel end assembly 234 defines a first wheel end axis 254, which is the axis of rotation of the first hub 46 and wheel 36 (or wheel 42 on the right side of the work vehicle 10), the first wheel end shaft 240, and the first wheel end sprocket 238 when driven by the center sprocket 140 via the first chain 142. The first wheel end axis 254 is substantially parallel to the pivot axis 60. A first distance 256 ( Figure 7 ). The wheel end shaft 240 of the second wheel end assembly 236 defines a second wheel end axis 258, which is the axis of rotation of the second wheel hub 46 and wheel 38 (or wheel 44 on the right side of the work vehicle 10), the second wheel end shaft 240, and the second wheel end sprocket 238 when driven by the center sprocket 140 via the second chain 146. The second wheel end axis 258 is substantially parallel to the pivot axis 60. A second distance 260 is defined from the second wheel end axis 258 to the pivot axis 60 ( Figure 7 ). Thus, when the center sprocket 140 rotates, the chains 142, 146 provide for the common rotation of the wheel end sprockets 238 of the wheel end assemblies 34, 36 and the rotation of the wheels 36, 38, 42, 44.

[0050] To propel the work vehicle 10, the engine 50 provides power to the transmission 52, which drives the differential 100, the first inner shaft 110, and the first outer shaft 116. The first outer shaft 116, in turn, drives the center sprocket 140 in each tandem wheel housing 72. The center sprocket 140 drives the first chain 142 and the second chain 146, which respectively rotate the first and second wheel end sprockets 238 and similarly the first and second wheel end shafts 240 to ultimately rotate the pair of right wheels 36, 38 mounted on the wheel end assemblies 234, 236 (or ultimately rotate the pair of left wheels 36, 38 mounted on the wheel end assemblies 234, 236 in the left tandem wheel housing 72). The transmission 52 typically includes one or more gear arrangements and / or clutches (not shown) to modify the speed of the input from the engine 50 to one or more speeds appropriate for the tandem wheel assemblies 32. Further gear reduction may be accomplished via planetary gear sets 118 between the first inboard shaft 110 and the first outboard shaft 116, and via planetary gear sets 119 between the second inboard shaft 112 and the second outboard shaft 117. If desired, gear reduction via planetary gear sets (not shown) or the like may be provided between the first wheel end sprocket 238 and the first left wheel 36, and likewise between the second wheel end sprocket 238 and the second left wheel 38.

[0051] The first distance 256 and / or the second distance 260 of each tandem wheel assembly 32 can be varied by moving (e.g., translating or sliding) one or both of the wheel end assemblies 234, 236 in a fore-aft direction relative to the outer wall 162 of the tandem wheel housing 72. The distance between the first distance 256 and the second distance 260 defines a wheelbase 262 of the work vehicle 10. Each tandem wheel housing 72 includes an adjustment feature 300 to allow movement of one or both of the wheel end assemblies 234, 236 relative to the outer wall 162 of the tandem wheel housing 72.

[0052] In one or more exemplary embodiments, the adjustment feature 300 includes an adjustment opening 302 radially circumscribing the opening 244 through the outer wall 162 of each tandem wheel housing 72, an adjustment opening 304 through the mounting flange 246 of each wheel end housing 242 of each tandem wheel housing 72, and a pin fastener 306. When at the desired distances 256, 260, the pin fastener 306 is positioned through each set of adjustment openings 302, 304 and securely secures each wheel end housing 242 to the tandem wheel housing 72. The pin fastener 306 can be a bolt or other elongated pin-type structure with or without threads. The adjustment openings 302 passing through the outer wall 162 surrounding each opening 244 can fall along an imaginary circle. The adjustment openings 302 can be spaced radially outward at the same distance from the center 245 of the corresponding opening 244. The adjustment openings 304 passing through the mounting flange 246 can fall along an imaginary circle. The adjustment openings 304 can be spaced radially outward at the same distance from the center of the corresponding wheel end shaft 240. In some embodiments, the openings 302, 304 are provided at the 0, 90, 180, and 270 degree positions, and areas therebetween, around each of the openings 244, and around the mounting flange 246.

[0053] like Figures 5 to 8As shown in FIG, adjustment opening 302 is an elongated slot having a long dimension in the fore-aft direction substantially parallel to first distance 256 and second distance 260, and adjustment opening 304 is a circular aperture, channel, or hole. Adjustment opening 304 is aligned with or positioned above adjustment opening 302 in each wheel end assembly 234, 236. Thus, wheel end assemblies 234 and / or 236 can be slid along the exterior of outer wall 162 toward or away from pivot axis 60 to position wheel end assemblies 234 and / or 236 at a desired distance from pivot axis 60, allowing distances 256 and / or 260 to be varied to change wheelbase 262. Depending on the adjusted position, the center 245 of opening 244 and the center of wheel end axle 240 can be aligned or offset in the fore-aft direction. Opening 302 always remains covered by the corresponding mounting flange 246. The amount of sliding movement is controlled by the length of slot 302. Thus, distances 256 and 260 can be easily varied to provide different wheelbases 262.

[0054] As the wheel end assembly 234 slides, the wheel end axle 240 of the wheel end assembly 234 slides along the opening 244 in the outer wall 162. The chain 142 becomes tensioned between the sprockets 140, 238. Similarly, as the wheel end assembly 236 slides, the wheel end axle 240 of the wheel end assembly 236 slides along the opening 244 in the outer wall 162, and the chain 146 becomes tensioned between the sprockets 140, 238. After the wheel end assemblies 234 and / or 236 are moved to provide the desired distances 256 and / or 260, fasteners 306 are inserted through the aligned sets of adjustment openings 302, 304 to attach the wheel end housing 242 in position relative to the tandem wheel housing 72. Because the adjustment opening 302 is a slot, this allows for an unlimited number of positions of the wheel end assemblies 234 and / or 236 relative to the outer wall 162 along the length of the adjustment opening 302. To secure the pins 306 to the outer wall 162, a nut 307 can be attached to the shaft of each fastener 306 within the interior volume 164. To accomplish this, the access panel 252 can be removed to allow access to the fasteners 306. In some embodiments, close-fitting bolt holes or dowel pins with tight clearances can be utilized in some of the openings 302, 304, for example at the 0 degree and 180 degree positions falling along the longitudinal axis 173 of the tandem wheel housing 72, to maintain the longitudinal centerline of the tandem wheel housing 72 during sliding movement.

[0055] The adjustment feature 300 also includes one or more tensioning mechanisms for applying a mechanical advantage to move the wheel end assemblies 234, 236 in the fore-aft direction relative to the corresponding outer wall 162 to change the relative positions of the wheel end assemblies 234, 236 along the first distance 256 and / or the second distance 260. In some embodiments, such a tensioning mechanism can be in the form of a manual jackscrew tensioner, including a wheel end bracket 316 extending laterally outward from the mounting flange 246, a housing bracket 318 extending laterally outward from the outer wall 162 and longitudinally aligned with the wheel end bracket 316, and a jackscrew 320 extending through an opening in the bracket 316, 318. The jackscrew 320 can be mounted solely for rotation on the housing bracket 318. As the jackscrew 320 rotates, the associated wheel end assembly 234, 236 moves in the fore-aft direction relative to the outer wall 162 depending on how the jackscrew 320 is rotated. Alternatively, a bolt or other pin structure may be provided that couples the brackets 316, 318 together and permits adjustment of the fore-aft spacing between the brackets 316, 318. One or both openings in the brackets 316, 318 may be threaded, and a set screw 320 or bolt may engage the threaded opening such that rotation of the set screw 320 or bolt in either clockwise direction causes the brackets 316, 318 to move closer or further relative to each other. An alternative tensioning mechanism may include unthreaded openings in the brackets 316, 318 and separate threaded nuts for threadably engaging the bolts. In other cases, the brackets 316, 318 may not be required, and an integral feature of the tandem wheel housing 72 and wheel end assemblies 234, 236 may define an opening or threaded opening that engages a pin connector (e.g., a bolt). Other tensioning mechanisms, including variable links, are contemplated that may be manually or powered (e.g., electrically or hydraulically actuated) and controlled by the control system 28.

[0056] Thus, adjustment feature 300 allows each wheel-end housing 242 to be repositioned relative to tandem wheel housing 72 to adjust the fore-aft distance of each wheel-end sprocket 238 from center sprocket 140. The dimension (i.e., the long dimension of the slot forming opening 302) primarily defines the extent to which the fore-aft distance can be varied. Depending on the amount of adjustment, one or both of the chains 142, 146 may need to be resized. This may include, for example, replacing chains 142, 146 with shorter or longer chains in the case of a continuous chain without a master link, or removing or adding links in the case of a resizable chain. Alternatively, or in addition, a chain tensioning mechanism may be included in the tandem wheel assembly to accommodate the adjustment of the wheel-end spacing with the correctly sized chain. In some embodiments, the adjusted fore-aft position of the wheel ends can be accommodated by substituting sprockets of different sizes (including replacing one or both of the center sprocket and the wheel-end sprockets). In some cases, both the sprockets and the chain may be resized.

[0057] In certain embodiments, the operating elements of the tandem wheel assembly 32 can be partially or completely flooded with lubricant (e.g., lubricating oil and cooling oil), thereby providing a "wet" environment. The inwardly facing surface 246a of the mounting flange 246 closes the opening 302 to substantially block fluid from passing through the opening 302. When the fastener 306 is seated within the adjustment opening 304, the substantially tight fit provides a fluid-tight seal between the fastener 306 and the mounting flange 246, substantially preventing lubricant from leaking therethrough. To further contain lubricant passing through the interface between the tandem wheel housing 72 and the wheel end housing 242, a sliding face seal 308 is provided between the tandem wheel housing 72 and each wheel end housing 242. During movement of the wheel end housing 242 relative to the outer wall 162, each face seal 308 forms a radially outward perimeter of the openings 302 and 304 to consistently circumscribe the openings 302 and 304. The sliding face seal 308 can be an O-ring or other gasket. The face seal 308 is seated in a recess or groove 310 in the outer wall 162 and extends partially outward from the outer wall 162. When the wheel end housing 242 is seated against the outer wall 162, the face seal 308 is compressed between the outer wall 162 and the wheel end housing 242 to form a fluid-tight but sliding seal. As the wheel end housing 242 slides relative to the outer wall 162, the face seal 308 remains seated in the groove 310 and maintains sealing contact with the inwardly facing surface 246a of the corresponding mounting flange 246. The face seal 308 is positioned a suitable distance outward of the opening 302 so that the opening 304 in the wheel end housing 242 remains within the perimeter defined by the face seal 308 during all possible movements of the wheel end housing 242 relative to the outer wall 162. Although the face seal 308 is shown seated within a recess or groove 310 in the outer wall 162 , it should be understood that the face seal 308 may be seated within a recess or groove in the inboard facing surface 246 a of the mounting flange 246 and move with the corresponding wheel end housing 242 .

[0058] In an embodiment, for example Figures 11 to 13As shown in FIG, the adjustment opening 302 can be a circular aperture, and the adjustment opening 304 can be an elongated slot having a long dimension in the fore-aft direction that is substantially parallel to the first distance 256 and the second distance 260. After the wheel end assembly 234 and / or 236 is moved to provide the desired distances 256 and / or 260, fasteners 306 inserted through the aligned set of adjustment openings 302, 304 secure the wheel end housing 242 in position relative to the tandem wheel housing 72. In this example, the openings 302 can be tapped so that their threads can engage with the threads of the fasteners 306 to secure the wheel end housing 242 without other receiving fasteners (e.g., nuts), allowing adjustment to be performed without opening the access panel 252. When the tandem wheel assembly 32 is used in a "wet" environment, the engaged threads of the fasteners 306 within the adjustment openings 302 provide a substantially fluid-tight seal between the fasteners 306 and the outer wall 162 to substantially prevent lubricant from leaking therethrough. To further contain lubricant passing between the interface between the tandem wheel housing 72 and the wheel end housing 242, at least one sliding face seal 308 is disposed between the tandem wheel housing 72 and each wheel end housing 242. As shown, each face seal 308 forms an inwardly facing perimeter of the openings 302 and 304 at all times during movement of the wheel end housing 242 relative to the outer wall 162. While the face seals 308 are shown seated within a recess or groove 312 in the inboard-facing surface 246a of the mounting flange 246, it should be understood that the face seals 308 may be seated within a recess or slot in the outer wall 162.

[0059] In other embodiments (not shown), the adjustment openings 302 and / or 304 may be a series of discrete circular apertures (not shown) spaced apart in the fore-aft direction through the outer wall 162 of the mounting flange 246. To position the wheel end assembly 234 and / or 236 at a desired location on the outer wall 162, after the wheel end assembly 234 and / or 236 is slid into the desired location, the desired circular apertures of the discrete circular apertures are aligned and the fastener 306 is inserted through the desired circular aperture. Here, the adjustment is provided at discrete fore-aft locations, rather than providing continuous or infinite adjustment between the ends of the opening 302 as would be the case if defined as an elongated slot. When operating in a wet environment, one or more sliding face seals (inwardly and / or outwardly of the adjustment openings) may be provided to substantially prevent leakage of lubricant passing through the interface between the tandem wheel housing 72 and the wheel end housing 242. In other embodiments (not shown), the adjustment openings 302 and / or 304 may be a series of discrete, spaced-apart, side-by-side circular apertures disposed through the outer wall 162 and the mounting flange 246. To position the wheel end assembly 234 and / or 236 at a desired location on the outer wall 162, after the wheel end assembly 234 and / or 236 is slid to the desired location, the desired ones of the discrete circular apertures are aligned and the fastener 306 is inserted through the desired circular aperture.

[0060] In other embodiments (not shown), both of the adjustment openings 302 and 304 may be elongated slots. In such embodiments, each of the adjustment openings 302 has a long dimension in the fore-aft direction that is substantially parallel to the first distance 256 and the second distance 260, and each of the adjustment openings 304 has a long dimension in the fore-aft direction that is substantially parallel to the first distance 256 and the second distance 260. Such embodiments may be used in limited "wet" or "dry" environment applications where the internal components are not immersed in lubricant. In such embodiments, after the wheel end assemblies 234 and / or 236 are moved to the desired distances 256 and / or 260, fasteners 306 extending through the aligned set of adjustment openings 302 and 304 secure the wheel end housing 242 in position relative to the tandem wheel housing 72. Because both openings 302 and 304 are elongated, the fore-aft adjustment distance may be increased in such embodiments compared to embodiments in which either of the openings 302 and 304 is round (i.e., non-elongated).

[0061] The foregoing describes one or more exemplary tandem wheel assemblies in detail. Various other configurations are possible within the scope of the present disclosure. For example, the disclosed dual-ring, dual-chain drive in the tandem wheel housing can be replaced with a single-ring center sprocket and a single chain coupling the center sprocket to the two wheel end sprockets.

[0062] Enumeration Example

[0063] Furthermore, the following examples are provided, which are numbered for ease of reference.

[0064] 1. A tandem wheel assembly for a work vehicle, comprising: a tandem wheel housing having a central opening disposed about a pivot axis and first and second wheel end openings disposed about associated first and second wheel axes substantially parallel to the pivot axis; a center sprocket disposed within the tandem wheel housing and rotatable about the pivot axis; and a first wheel end assembly and a second wheel end assembly, the first wheel end assembly and the second wheel end assembly comprising: first and second wheel end axles extending through associated first and second wheel end openings of the tandem wheel housing; first and second wheel end sprockets, the The first and second wheel end sprockets are mounted to the associated first and second wheel end axles and aligned within the tandem wheel housing to engage the center sprocket by means of at least one chain, the at least one chain transmitting rotation of the center sprocket about the pivot axis to rotate the first and second wheel end sprockets about the associated first and second wheel axes; and first and second wheel end housings supporting the first and second wheel end axles for relative rotation about the associated first and second wheel axes; wherein the first wheel end housing is adjustably mounted to the tandem wheel housing to vary a first distance between the pivot axis and the first wheel axis.

[0065] 2. The tandem wheel assembly of example 1, wherein the second wheel end housing is adjustably mounted to the tandem wheel housing to vary a second distance between the pivot axis and the second wheel axis.

[0066] 3. The tandem wheel assembly of Example 2, wherein at least one of the tandem wheel housing, the first wheel end housing, and the second wheel end housing includes one or more adjustment openings configured to vary at least one of the first and second distances.

[0067] 4. The tandem wheel assembly of example 3, wherein the one or more adjustment openings are slots having a long dimension extending substantially parallel to the first distance.

[0068] 5. The tandem wheel assembly of Example 3, wherein a plurality of the adjustment openings are provided in an outer wall of the tandem wheel housing and are proximate to the first and second wheel end openings.

[0069] 6. The tandem wheel assembly of example 3, wherein a plurality of said adjustment openings are provided in the mounting flanges of said first and second wheel end housings.

[0070] 7. The tandem wheel assembly according to Example 1 further includes an adjustment mechanism installed between the tandem wheel housing and the first wheel end housing, the adjustment mechanism having a movable member, and the movable member is configured to apply a force to move the first wheel end housing relative to the tandem wheel housing along the first distance.

[0071] 8. A tandem wheel assembly according to Example 7, wherein the adjustment mechanism includes: a wheel end bracket, which is fixed to the first wheel end shell and has an opening; a shell bracket, which is fixed to the tandem wheel shell and has an opening; and a pin, which is arranged to pass through the openings of the wheel end bracket and the shell bracket; wherein the adjustment mechanism is configured to change the relative position of the wheel end bracket and the shell bracket along the first distance.

[0072] 9. The tandem wheel assembly of Example 8, wherein the pin is threaded and at least one of the openings of the wheel end bracket and the housing bracket is threaded, whereby rotation of the pin changes the relative position of the wheel end bracket and the housing bracket.

[0073] 10. The tandem wheel assembly of Example 9, wherein both the wheel end bracket and the opening of the housing bracket are threaded, and the pin is threadably engageable with both the opening of the wheel end bracket and the opening of the housing bracket.

[0074] 11. The tandem wheel assembly according to Example 2 further includes an adjustment mechanism installed between the tandem wheel housing and each of the first and second wheel end housings, the adjustment mechanism being configured to apply a force to move the first and second wheel end housings relative to the tandem wheel housing along the associated first and second directions.

[0075] 12. The tandem wheel assembly according to Example 1 further includes first and second seals surrounding the first and second wheel end openings of the tandem wheel housing and between the tandem wheel housing and the associated first and second wheel end housings; wherein the first and second seals are fixed relative to the tandem wheel housing or the associated first and second wheel end housings; and wherein the first seal implements a sliding surface seal during adjustment of the first wheel end housing relative to the tandem wheel housing; wherein at least one of the tandem wheel housing and the first wheel end housing includes one or more adjustment openings configured to vary the first distance; and wherein the first seal is arranged around the one or more adjustment openings.

[0076] 13. The tandem wheel assembly according to Example 2 further includes first and second seals surrounding the first and second wheel end openings of the tandem wheel housing and between the tandem wheel housing and the associated first and second wheel end housings; wherein the first and second seals are fixed relative to the tandem wheel housing or the associated first and second wheel end housings; and wherein the first and second seals implement sliding surface seals during adjustment of the first and second wheel end housings relative to the tandem wheel housing.

[0077] 14. A tandem wheel assembly according to Example 13, wherein at least one of the tandem wheel housing, the first wheel end housing and the second wheel end housing includes one or more adjustment openings configured to vary the first and second distances; and wherein the first and second seals are arranged around the associated first and second wheel end openings and the associated adjustment openings in the one or more adjustment openings.

[0078] 15. A tandem wheel assembly according to Example 1, wherein the center sprocket is a double sprocket having first and second chain rings; and wherein the at least one chain includes a first and a second chain, the first chain engaging the first chain ring of the center sprocket and the first wheel end sprocket, and the second chain engaging the second chain ring of the center sprocket and the second wheel end sprocket.

[0079] in conclusion

[0080] The examples discussed above lead to various benefits of the disclosed tandem wheel assembly. For example, the coupling of the tandem wheel housing and wheel ends allows the front-to-rear wheelbase of the tandem wheel assembly to be varied. This allows the same tandem wheel housing and wheel ends to be utilized in different work vehicle models having different tandem wheelbases, thereby reducing inventory and manufacturing costs.

[0081] The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the present disclosure. Unless expressly indicated otherwise, as used herein, the singular forms "a," "an," and "the" are intended to include the plural meaning. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or parts, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, and / or groups thereof.

[0082] The description of the present disclosure has been presented for the purpose of illustration and description, but is not intended to be exhaustive or limited to the disclosure of the disclosed form. Without departing from the scope and spirit of the present disclosure, many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments explicitly cited herein have been selected and described to best explain the principles of the present disclosure and its practical application, and to enable other persons of ordinary skill in the art to understand the present disclosure and to recognize many replacements, modifications and variations to the described (multiple) examples. Therefore, various embodiments and implementations other than those explicitly described are within the scope of the appended claims.

Claims

1. A tandem wheel assembly (32) for a work vehicle (10), comprising: a tandem wheel housing (72) having a central opening (83) and first and second wheel end openings, the central opening (83) being disposed about a pivot axis (60), the first and second wheel end openings being disposed about associated first and second wheel axes that are substantially parallel to the pivot axis (60); a center sprocket (140) located within the tandem wheel housing (72) and rotatable about the pivot axis (60); A first wheel end assembly (234) and a second wheel end assembly (236), wherein the first wheel end assembly (234) and the second wheel end assembly (236) include: a first wheel end axle and a second wheel end axle extending through an associated first wheel end opening and an associated second wheel end opening of the tandem wheel housing (72); a first wheel end sprocket and a second wheel end sprocket mounted to associated first wheel end axles and associated second wheel end axles and aligned within the tandem wheel housing (72) to engage the center sprocket (140) by means of at least one chain, the at least one chain transmitting rotation of the center sprocket (140) about the pivot axis (60) to rotate the first wheel end sprocket and the second wheel end sprocket about associated first wheel axes and associated second wheel axes; and first and second wheel end housings supporting the first and second wheel end axles for relative rotation about associated first and second wheel axes; wherein the first wheel end housing is adjustably mounted to the tandem wheel housing (72) to vary a first distance between the pivot axis (60) and the first wheel axis; and a first seal and a second seal surrounding the first wheel end opening and the second wheel end opening of the tandem wheel housing (72) and between the tandem wheel housing (72) and the associated first wheel end housing and the associated second wheel end housing; wherein the first seal and the second seal are fixed relative to the tandem wheel housing (72) or relative to the associated first wheel end housing and the associated second wheel end housing; The first seal forms a sliding surface seal during adjustment of the first wheel end housing relative to the tandem wheel housing (72).

2. The tandem wheel assembly (32) according to claim 1, wherein: The second wheel end housing is adjustably mounted to the tandem wheel housing (72) to vary a second distance between the pivot axis (60) and the second wheel axis.

3. The tandem wheel assembly (32) according to claim 2, wherein: At least one of the tandem wheel housing (72), the first wheel end housing, and the second wheel end housing includes one or more adjustment openings (302, 304) configured to vary at least one of the first distance and the second distance.

4. The tandem wheel assembly (32) according to claim 3, wherein: The one or more adjustment openings (302, 304) are slots having a long dimension extending substantially parallel to the first distance.

5. The tandem wheel assembly (32) according to claim 3, wherein: The plurality of adjustment openings (302, 304) are disposed in the outer wall (162) of the tandem wheel housing (72) and are proximate to the first wheel end opening and the second wheel end opening.

6. The tandem wheel assembly (32) according to claim 3, wherein: A plurality of adjustment openings (302, 304) are provided in the mounting flange of the first wheel end housing and the mounting flange of the second wheel end housing.

7. The tandem wheel assembly (32) according to claim 1 further includes an adjustment mechanism (300) installed between the tandem wheel housing (72) and the first wheel end housing, the adjustment mechanism (300) having a movable member, the movable member being configured to apply a force to move the first wheel end housing relative to the tandem wheel housing (72) along the first distance.

8. The tandem wheel assembly (32) according to claim 7, wherein: The regulating mechanism (300) comprises: a wheel end bracket (316) fixed to the first wheel end housing and having an opening; a housing bracket (318) secured to the tandem wheel housing (72) and having an opening; and a top screw, the top screw being arranged to pass through an opening of the wheel end bracket (316) and an opening of the housing bracket (318); The adjustment mechanism (300) is configured to change the relative position of the wheel end bracket (316) and the housing bracket (318) along the first distance.

9. The tandem wheel assembly (32) according to claim 8, wherein: The top screw is threaded, and at least one of the opening of the wheel end bracket (316) and the opening of the housing bracket (318) is threaded, whereby rotation of the top screw changes the relative position of the wheel end bracket (316) and the housing bracket (318).

10. The tandem wheel assembly (32) according to claim 9, wherein: Both the opening of the wheel end bracket (316) and the opening of the housing bracket (318) are threaded, and the top screw is threadably engaged with both the opening of the wheel end bracket (316) and the opening of the housing bracket (318).

11. The tandem wheel assembly (32) of claim 2, further comprising an adjustment mechanism (300) mounted between the tandem wheel housing (72) and each of the first wheel end housing and the second wheel end housing, the adjustment mechanism (300) being configured to apply a force to move the first wheel end housing and the second wheel end housing relative to the tandem wheel housing (72) along an associated first direction and an associated second direction.

12. The tandem wheel assembly (32) according to claim 1, in, At least one of the tandem wheel housing (72) and the first wheel end housing includes one or more adjustment openings (302, 304) configured to vary the first distance; and Wherein, the first sealing member is arranged around the one or more adjustment openings (302, 304).

13. The tandem wheel assembly (32) according to claim 2, in, The second seal implements a sliding surface seal during adjustment of the second wheel end housing relative to the tandem wheel housing (72).

14. The tandem wheel assembly (32) according to claim 13, wherein: At least one of the tandem wheel housing (72), the first wheel end housing, and the second wheel end housing includes one or more adjustment openings (302, 304) configured to vary the first distance and the second distance; and The first seal and the second seal are disposed around an associated first wheel end opening and an associated second wheel end opening and around an associated adjustment opening of the one or more adjustment openings (302, 304).

15. The tandem wheel assembly (32) of claim 1, wherein: The center sprocket (140) is a double sprocket having a first chain ring and a second chain ring; and wherein the at least one chain comprises a first chain (142) and a second chain (146), the first chain (142) engaging the first chain ring of the center sprocket (140) and the first wheel end sprocket, and the second chain (146) engaging the second chain ring of the center sprocket (140) and the second wheel end sprocket.

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