Suspension systems for a power machine

Abstract

A power machine (100, 200, 300) can include a frame (110, 210, 310) that can include a front frame member (212, 312), a rear frame member (214, 314) that is pivotally coupled to the front frame member at a frame joint (216, 316), and a power source supported by the frame (110, 210, 310). A tractive system (240, 340) can include at first axle (328A) that is operably engaged with a first drive motor (326A) that is powered by the power source, and a suspension system (382A) can support the first axle (328A) and the first drive motor (326A) relative to the front frame member (312, 312) or the rear frame member (214, 314).

Description

SUSPENSION SYSTEMS FOR A POWER MACHINECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 596,059, filed November 3, 2023, which is hereby incorporated by reference in its entirety.BACKGROUND

[0002] This disclosure is directed toward power machines. More particularly, the present disclosure is directed to articulated loaders that have a front frame member and a rear frame member pivotably coupled to the front frame member about a vertical axis. Power machines, for the purposes of this disclosure, include any type of machine that generates power to accomplish a particular task or a variety of tasks. One type of power machine is a work vehicle. Work vehicles are generally self-propelled vehicles that have a work device, such as a lift arm (although some work vehicles can have other work devices) that can be manipulated to perform a work function. Work vehicles include loaders (including mini-loaders), excavators, utility vehicles, mowers, tractors (including compact tractors), and trenchers, to name a few examples.

[0003] The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.SUMMARY

[0004] Power machines and related systems and methods as disclosed herein, including articulated loaders in particular, can include different systems to improve functionality and operator experience while operating the machine. For example, among other improvements, different implementations can provide power machines with improved suspension systems that can enhance operator experience and generally reduce forces transmitted to components of the power machine while operating the power machine over unpaved terrain.

[0005] Some aspects of the disclosure provide a power machine. The power machine can include a frame that includes a front frame member and rear frame member that is pivotally coupled to the front frame member at a frame joint, a power source supported by the frame, a tractive system that includes a first axle that is operably engaged with a first drive motor powered by the power source, and a suspension system that moveably supports the first axle and the first drive motor relative to the front frame member or the rear frame member.

[0006] Some aspects of the disclosure can provide the power machine of any previous aspect in which the first axle is cantilevered from the front frame member or the rear frame member by the suspension system.

[0007] Some aspects of the disclosure can provide the power machine of any previous aspect in which the suspension system includes a torsion member supported by the frame a lever member that is coupled to the torsion member at a first end and coupled to the first axle at a second end.

[0008] Some aspects of the disclosure can provide the power machine of any previous aspect in which the suspension system includes a torsion pad secured relative to the frame to resiliently respond to torsional force applied to the torsion member by movement of the lever member relative to the frame.

[0009] Some aspects of the disclosure can provide the power machine of any previous aspect in which the torsion member is at least partially housed within a suspension housing secured to the frame, and in which the torsion pad is arranged within the suspension housing.

[0010] Some aspects of the disclosure can provide the power machine of any previous aspect in which the torsion member is held within the suspension housing via a frictional force generated by the torsion pad.

[0011] Some aspects of the disclosure can provide the power machine of any previous aspect in which the torsion member defies a rectangular cross-section, the suspension housing defines a rectangular cross-section, and the torsion member is arranged within the suspension housing at about a 45-degree offset relative to the suspension housing.

[0012] Some aspects of the disclosure can provide the power machine of any previous aspect in which the frame includes an oblong opening corresponding to the first axle, and the first drive motor extends from a suspension arm of the suspension system through the oblong opening to permit movement of the first axle relative to the frame via movement of the suspension system.

[0013] Some aspects of the disclosure can provide the power machine of any previous aspect including a locking pin arranged between the suspension system and the frame to selectively lock movement of the first axle relative to the frame.

[0014] Some aspects of the disclosure provide a power machine. The power machine can include a frame that is pivotable at a frame joint, a power source supported by the frame, atractive system that includes a first axle that is operably engaged with a first drive motor powered by the power source, and a suspension system to permit movement of the first axle relative to the frame. The suspension system can include a first torsion member supported by the frame and a first suspension arm coupled to the first torsion member at a first end and to the first axle at a second end to permit vertical movement of the first axle relative to the first torsion member.

[0015] Some aspects of the disclosure can provide the power machine of any previous aspect in which the frame includes a front frame member and a rear frame member that is pivotally coupled to the front frame member at the frame joint and in which the suspension system includes a first suspension assembly supported by the front frame member, the first suspension assembly including the first torsion member coupled to the front frame member and the first suspension arm cantilevers the first axle relative to the first torsion member and a second suspension assembly supported by the rear frame member, the second suspension assembly including a second torsion member coupled to the rear frame member, and a second suspension arm coupled to the second torsion member and to a second axle to cantilever the second axle relative to the second torsion member.

[0016] Some aspects of the disclosure can provide the power machine of any previous aspect in which, relative to a front-to-back direction of the front frame member, the first suspension arm extends forward of the first torsion member to support the first axle and in which, relative to a front-to-back direction of the rear frame member, the second suspension arm extends rearward of the second torsion member to support the second axle.

[0017] Some aspects of the disclosure can provide the power machine of any previous aspect in which an end portion of the first suspension arm extends past the first axle in a direction away from the first torsion member and a guide structure extending from the frame engages the end portion to limit lateral deflection of the first suspension arm.

[0018] Some aspects of the disclosure can provide the power machine of any previous aspect in which the suspension system includes a torsion pad configured to resiliently resist torsional force applied to the torsion member.

[0019] Some aspects of the disclosure can provide the power machine of any previous aspect in which the torsion member is received within a first suspension housing that is secured to and extends laterally across the frame, the torsion pad being arranged within the suspension housing to engage the torsion member.

[0020] Some aspects of the disclosure can provide the power machine of any previous aspect in which the torsion member defies a rectangular cross-section, the first suspension housing defines a rectangular cross-section, and the torsion member is arranged within the first suspension housing at a 45-degree offset relative to the first suspension housing.

[0021] Some aspects of the disclosure can provide the power machine of any previous aspect including a second suspension system to permit movement of a second axle relative to the frame, the second axle being laterally opposite the first axle relative to a front-to-back direction of the power machine. The second suspension system including a second torsion member supported by the frame and a second suspension arm coupled to the second torsion member at a first end and to the second axle at a second end to permit vertical movement of the second axle relative to the second torsion member. The second torsion member is received within a second suspension housing that is secured to and extends laterally across the frame, laterally opposite the first suspension housing, to engage a second torsion pad arranged within the second suspension housing.

[0022] Some aspects of the disclosure can provide a method of assembling a power machine. The method can include securing a suspension housing of a suspension assembly to one of a front frame member or a rear frame member of a frame of the power machine, the front frame member being pivotally coupled to the rear frame member at a frame joint, arranging a torsion member of the suspension assembly to extend into the suspension housing, and moveably supporting an axle of the power machine relative to the one of the front frame member or the rear frame member via a suspension arm of the suspension assembly that is secured to the torsion member.

[0023] Some aspects of the disclosure can provide the method of any previous aspect including arranging a torsion pad within the suspension housing, the torsion pad engaging at least a portion of a perimeter of the torsion member to resiliently resist torsional force applied to the torsion member.

[0024] Some aspects of the disclosure can provide the power machine of any previous aspect including securing a second suspension housing of a second suspension assembly to the other of the front frame member or the rear frame member, arranging a second torsion member of the second suspension assembly to extend into the second suspension housing, and moveably supporting a second axle of the power machine relative to the other of the front frame member or the rear frame member via a second suspension arm of the second suspension assembly thatis secured to the second torsion member. The suspension arm extending in a first direction from the torsion member to the axle, relative to a front-to-back axis of the power machine, and the second suspension arm extending from the second torsion member to the second axle in a second direction that is opposite the first direction, relative to the front-to-back axis.

[0025] This Summary and the Abstract are provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor are they intended to be used as an aid in determining the scope of the claimed subject matter.DRAWINGS

[0026] The following drawings are provided to help illustrate various features of nonlimiting examples of the present disclosure and are not intended to limit the scope of the disclosure or exclude alternative implementations.

[0027] FIG. 1 is a block diagram illustrating functional systems of a representative power machine on which examples of the present disclosure can be advantageously practiced.

[0028] FIGS. 2 and 3 illustrate perspective views of a representative power machine in the form of a small articulated loader of the type on which the disclosed examples can be advantageously practiced.

[0029] FIG. 4 is a block diagram illustrating components of a hydraulic power system for a power machine, including the loader illustrated in FIGS. 2 and 3.

[0030] FIG. 5 is a schematic view of a representative frame of a power machine having a suspension system in accordance with aspects of the present disclosure.

[0031] FIG. 6 is a perspective view of another representative example of the power machine of FIG. 5 having a suspension system in accordance with aspects of the present disclosure.

[0032] FIG. 7 is a bottom view of the power machine of FIG. 6.

[0033] FIG. 8 is side elevation, partially schematic view of the power machine of FIG. 6.

[0034] FIGS. 9-13 are various views of another example suspension system of the power machine of FIG. 6, in accordance with aspects of the present disclosure, with external components of the power machine removed for clarity of presentation.

[0035] FIG. 14 is a detailed view of a front suspension assembly of the suspension system of FIGS. 9-13, with front axle assemblies removed.

[0036] FIGS. 15 and 16 are perspective and front elevation views of the front suspension assembly of the suspension system of FIGS. 9-13.

[0037] FIG. 17 is a cross-sectional view taken along line XVII-XVII of FIG. 16.

[0038] FIG. 18 is a detailed view of a rear suspension assembly of the suspension system of FIGS. 9-13.

[0039] FIGS. 19-21 are various views of another example configuration of the suspension system of the power machine of FIGS. 9-18, in accordance with aspects of the present disclosure.

[0040] FIG. 22 is a side elevation view of yet another example suspension system of the power machine of FIG. 5 or the power machine of FIG. 6, in accordance with aspects of the present disclosure, with external components of the power machine removed for clarity of presentation.

[0041] FIG. 23 is an axonometric view of another example of a frame and corresponding suspension system for use with the power machine of FIGS. 2 and 3.

[0042] FIG. 24 is a bottom view of the frame and suspension system of FIG. 35.

[0043] FIG. 25 is an axonometric view of the suspension system of FIG. 35.

[0044] FIG. 26 is an axonometric view of a first weldment and attached motor of the suspension system of FIG. 25.

[0045] FIG. 27 is a first axonometric view of a second weldment of the suspension system of FIG. 25.

[0046] FIG. 28 is a second axonometric view of the second weldment of FIG. 27, including elastomer inserts.

[0047] FIG. 29 is a side elevation partial view of the suspension system of FIG. 25.

[0048] FIG. 30 is a side elevation view of the frame of FIG. 23.

[0049] FIG. 31 is an axonometric partial view of the frame and suspension system of FIG. 23.

[0050] FIG. 32 is a side elevation partial view of another example of a frame and corresponding suspension system for use with the power machines of FIGS. 2 and 3.DETAILED DESCRIPTION

[0051] The concepts disclosed in this discussion are described and illustrated by referring to exemplary implementations of the disclosed technology. These concepts, however, are not limited in their application to the details of construction and the arrangement of components in the illustrative examples and are capable of being practiced or being carried out in various other ways. The terminology in this document is used for the purpose of description and should not be regarded as limiting. Words such as “including,” “comprising,” and “having” and variations thereof as used herein are meant to encompass the items listed thereafter, equivalents thereof, as well as additional items. In addition, any feature disclosed with respect to one embodiment may be included in another embodiment, and vice-versa.

[0052] Conventional power machines, and in particular power machines with articulated frames (e.g., articulated loaders), typically include one or more drive motor assemblies (e.g., including a drive motor and a wheel) attached directly to the rigid frame or frame members. As such, conventional articulated power machines commonly do not include a suspension system to permit movement of the drive motors (e.g., including the wheels) relative to the frame. Accordingly, forces may be transmitted relatively directly from the drive motor assemblies to the frame and then to an operator of the power machine. This can result in wear of components of the power machine as well as cause fatigue of the operator while operating the loader for an extended period of time over rough terrain. However, implementing conventional suspension systems in such a power machine may be overly expensive or may present significant packaging or manufacturing challenges (e.g., may require increases in width or internal volume of a frame of a power machine, or other increases an overall size and weight).

[0053] Examples of the present disclosure can address these problems, for example, by providing improved suspension systems for power machines, and particular for articulated loaders and other similar machines. In particular, some example suspension systems can include a torsion member (e.g., a torsion bar, supported by rubber spring members) and a lever member (e.g., a suspension arm, cantilevered from a power machine frame). The torsion member can be attached to a frame and can be coupled to a corresponding axle of the power machine by the lever member. For example, a first (proximal) end of the lever member can be rigidly secured to the torsion member and a second (distal) end of the lever member can be secured to an axle assembly for a wheel or other ground-engaging element (e.g., an axle assembly including an axle, a drive motor, associated shafts and bearings, etc.).

[0054] Such a configuration (and others disclosed herein) may generally require little or no added space within the frame, as compared to arrangements with no suspensions, and may extend the overall width of a power machine only minimally. Further, manufacturing may be relatively simple and inexpensive, in comparison to many conventional suspension systems for power machines. With torsion members attached to a bottom side of a frame, such a suspension system may also be easily serviceable (e.g., maintainable or replaceable) in comparison to conventional suspension systems with components arranged within the interior of the frame.

[0055] These concepts can be practiced on various power machines, as will be described below. A representative power machine on which the examples can be practiced is illustrated in diagram form in FIG. 1 and one example of such a power machine is illustrated in FIGS. 2 and 3 and described below before any examples are disclosed. For the sake of brevity, only one power machine is illustrated and discussed as being a representative power machine. However, as mentioned above, the examples below can be practiced on any of a number of power machines, including power machines of different types from the representative power machine shown in FIGS. 2 and 3. Power machines, for the purposes of this discussion, include a frame, at least one work element, and a power source that can provide power to the work element to accomplish a work task. One type of power machine is a self-propelled work vehicle. Self- propelled work vehicles are a class of power machines that include a frame, work element, and a power source that can provide power to the work element. At least one of the work elements is a motive system for moving the power machine under power.

[0056] FIG. 1 is a block diagram that illustrates the basic systems of a power machine 100, which can be any of a number of different types of power machines, upon which the examples discussed below can be advantageously incorporated. The block diagram of FIG. 1 identifies various systems on power machine 100 and the relationship between various components and systems. As mentioned above, at the most basic level, power machines for the purposes of this discussion include a frame, a power source, and a work element. The power machine 100 has a frame 110, a power source 120, and a work element 130. Because power machine 100 shown in FIG. 1 is a self-propelled work vehicle, it also has tractive elements 140, which are themselves work elements provided to move the power machine over a support surface and an operator station 150 that provides an operating position for controlling the work elements of the power machine. A control system 160 is provided to interact with the other systems to perform various work tasks at least in part in response to control signals provided by an operator. For example, the control system 160 can be an integrated or distributed architectureof one or more processor devices and one or more memories that are collectively configured to receive operator input or other input signals (e.g., sensor data) and to output commands accordingly for power machine operations.

[0057] Certain work vehicles have work elements that can perform a dedicated task. For example, some work vehicles have a lift arm to which an implement such as a bucket is attached such as by a pinning arrangement. The work element, i.e., the lift arm can be manipulated to position the implement to perform the task. The implement, in some instances can be positioned relative to the work element, such as by rotating a bucket relative to a lift arm, to further position the implement. Under normal operation of such a work vehicle, the bucket is intended to be attached and under use. Such work vehicles may be able to accept other implements by disassembling the implement / work element combination and reassembling another implement in place of the original bucket. Other work vehicles, however, are intended to be used with a wide variety of implements and have an implement interface such as implement interface 170 shown in FIG. 1. At its most basic, implement interface 170 is a connection mechanism between the frame 110 or a work element 130 and an implement, which can be as simple as a connection point for attaching an implement directly to the frame 110 or a work element 130 or more complex, as discussed below.

[0058] On some power machines, implement interface 170 can include an implement carrier, which is a physical structure movably attached to a work element. The implement carrier has engagement features and locking features to accept and secure any of a number of different implements to the work element. One characteristic of such an implement carrier is that once an implement is attached to it, it is fixed to the implement (i.e., not movable with respect to the implement) and when the implement carrier is moved with respect to the work element, the implement moves with the implement carrier. The term implement carrier as used herein is not merely a pivotal connection point, but rather a dedicated device specifically intended to accept and be secured to various different implements. The implement carrier itself is mountable to a work element 130 such as a lift arm or the frame 110. Implement interface 170 can also include one or more power sources for providing power to one or more work elements on an implement. Some power machines can have a plurality of work element with implement interfaces, each of which may, but need not, have an implement carrier for receiving implements. Some other power machines can have a work element with a plurality of implement interfaces so that a single work element can accept a plurality of implements simultaneously. Each of these implement interfaces can, but need not, have an implement carrier.

[0059] Frame 110 includes a physical structure that can support various other components that are attached thereto or positioned thereon. The frame 110 can include any number of individual components. Some power machines have frames that are rigid. That is, no part of the frame is movable with respect to another part of the frame. Other power machines have at least one portion that can move with respect to another portion of the frame. For example, excavators can have an upper frame portion that rotates with respect to a lower frame portion. Other work vehicles have articulated frames such that one portion of the frame pivots with respect to another portion for accomplishing steering functions.

[0060] Frame 110 supports the power source 120, which is configured to provide power to one or more work elements 130 including the one or more tractive elements 140, as well as, in some instances, providing power for use by an attached implement via implement interface 170. Power from the power source 120 can be provided directly to any of the work elements 130, tractive elements 140, and implement interface 170. Alternatively, power from the power source 120 can be provided to a control system 160, which in turn selectively provides power to the elements that capable of using it to perform a work function. Power sources for power machines typically include an engine such as an internal combustion engine and a power conversion system such as a mechanical transmission or a hydraulic system that is configured to convert the output from an engine into a form of power that is usable by a work element. Other types of power sources can be incorporated into power machines, including electrical sources or a combination of power sources, known generally as hybrid power sources.

[0061] FIG. 1 shows a single work element designated as work element 130, but various power machines can have any number of work elements. Work elements are typically attached to the frame of the power machine and movable with respect to the frame when performing a work task. For example, the power machine can be a mower with a mower deck or other mower component as a work element, which may be movable with respect to the frame of the mower. In addition, tractive elements 140 are a special case of work element in that their work function is generally to move the power machine 100 over a support surface. Tractive elements 140 are shown separate from the work element 130 because many power machines have additional work elements besides tractive elements, although that is not always the case. Power machines can have any number of tractive elements, some or all of which can receive power from the power source 120 to propel the power machine 100. Tractive elements can be, for example, track assemblies, wheels attached to an axle, and the like. Tractive elements can be mounted to the frame such that movement of the tractive element is limited to rotation about an axle (sothat steering is accomplished by a skidding action) or, alternatively, pivotally mounted to the frame to accomplish steering by pivoting the tractive element with respect to the frame.

[0062] Power machine 100 includes the operator station 150 that includes an operating position from which an operator can control operation of the power machine. In some power machines, the operator station 150 is defined by an enclosed or partially enclosed cab. Some power machines on which the disclosed examples may be practiced may not have a cab or an operator compartment of the type described above. For example, a walk behind loader may not have a cab or an operator compartment, but rather an operating position that serves as an operator station from which the power machine is properly operated. More broadly, power machines other than work vehicles may have operator stations that are not necessarily similar to the operating positions and operator compartments referenced above. Further, some power machines such as power machine 100 and others, whether or not they have operator compartments or operator positions, may be capable of being operated remotely (i.e., from a remotely located operator station) instead of or in addition to an operator station adjacent or on the power machine. This can include applications where at least some of the operator- controlled functions of the power machine can be operated from an operating position associated with an implement that is coupled to the power machine. Alternatively, with some power machines, a remote-control device can be provided (i.e., remote from both of the power machine and any implement to which is it coupled) that is capable of controlling at least some of the operator-controlled functions on the power machine.

[0063] FIGS. 2 and 3 illustrate a loader 200, which is one particular example of a power machine of the type illustrated in FIG. 1 where the examples discussed below can be advantageously employed. Loader 200 is an articulated loader with a front mounted lift arm assembly 230, which in this example is a telescopic lift arm. Loader 200 is one particular example of the power machine 100 illustrated broadly in FIG. 1 and discussed above. To that end, features of loader 200 described below include reference numbers that are generally similar to those used in FIG. 1. For example, loader 200 is described as having a frame 210, just as power machine 100 has a frame 110. The description herein of loader 200 with reference to FIGS. 2 and 3 provides an illustration of the environment in which the examples discussed below can be practiced and this description should not be considered limiting especially as to the description of features of the loader 200 that are not essential to the disclosed technology. Such features may or may not be included in power machines other than loader 200 upon which the examples disclosed below may be advantageously practiced. Unless specifically notedotherwise, examples disclosed below can be practiced on a variety of power machines, with the loader 200 being only one of those power machines. For example, some or all of the concepts discussed below can be practiced on many other types of work vehicles such as various other loaders, excavators, trenchers, and dozers, to name but a few examples.

[0064] Loader 200 includes frame 210 that supports a power system 220 that can generate or otherwise provide power for operating various functions on the loader 200. Frame 210 also supports a work element in the form of lift arm assembly 230 that is powered by the power system 220 and that can perform various work tasks. As loader 200 is a work vehicle, frame 210 also supports a traction system 240, which is also powered by power system 220 and can propel the loader 200 over a support surface. The lift arm assembly 230 in turn supports an implement interface 270 that includes an implement carrier 272 that can receive and secure various implements to the loader 200 for performing various work tasks and power couplers 274, to which an implement can be coupled for selectively providing power to such implement that might be connected to the loader 200. Power couplers 274 can provide sources of hydraulic or electric power or both. The loader 200 includes a cab 250 that defines an operator station 255 from which an operator can manipulate various control devices to cause the loader 200 to perform various work functions. Cab 250 includes a canopy 252 that provides a roof for the operator compartment and is configured to have an entry 254 on one side of an operator seat 258 (in the example shown in FIG. 3, the left side) to allow for an operator to enter and exit the cab 250. Although cab 250 as shown does not include any windows or doors, a door or windows can be provided.

[0065] The operator station 255 includes various operator input devices 260, including control levers that an operator can manipulate to control various machine functions. The operator input devices 260 can further include a steering wheel, buttons, switches, levers, sliders, pedals and the like that can be stand-alone devices such as hand operated levers or foot pedals or incorporated into hand grips or display panels, including programmable input devices. Actuation of operator input devices 260 can generate signals in the form of electrical signals, hydraulic signals, or mechanical signals. Signals generated in response to the operator input devices 260 are provided to various components on the loader 200 for controlling various functions on the loader 200 (e.g., via intervening electronic, hydraulic, or other control devices of generally known types). Among the functions that are controlled via the operator input devices 260 on loader 200 include control of the traction system 240, the lift arm assembly230, the implement carrier 272, and providing signals to any implement that may be operably coupled to the implement carrier 272.

[0066] Loaders can include human-machine interfaces including display devices that are provided in the cab 250 to give indications of information relatable to the operation of the power machines in a form that can be sensed by an operator, such as, for example, audible or visual indications. Audible indications can be made in the form of buzzers, bells, and the like or via verbal communication. Visual indications can be made in the form of graphs, lights, icons, gauges, alphanumeric characters, and the like. Displays can be dedicated to providing dedicated indications, such as warning lights or gauges, or dynamic to provide programmable information, including programmable display devices such as monitors of various sizes and capabilities. Display devices can provide diagnostic information, troubleshooting information, instructional information, and various other types of information that assists an operator with operation of the power machine or an implement coupled to the power machine. Other information that may be useful for an operator can also be provided. Other power machines, such as walk behind loaders, for example, may not have a cab nor an operator compartment, nor a seat. The operator position on such loaders is generally defined relative to a position where an operator is best suited to manipulate operator input devices.

[0067] Various power machines that can include or interact with the examples discussed below can have various different frame components that support various work elements. The elements of frame 210 discussed herein are provided for illustrative purposes and should not be considered to be the only type of frame that a power machine on which the examples can be practiced can employ. As mentioned above, loader 200 is an articulated loader and as such has two frame members that are pivotally coupled together at an articulation joint. For the purposes of this disclosure, frame 210 refers to the entire frame of the loader 200. Frame 210 of loader 200 includes a front frame member 212 and a rear frame member 214 that are coupled together at an articulation joint 216. Actuators are provided to rotate the front frame member 212 and the rear frame member 214 relative to each other about a pivot axis 217 to accomplish a turn of the loader 200.

[0068] The front frame member 212 supports and is operably coupled to the lift arm 230 at the articulation joint 216. A lift arm cylinder (positioned beneath the lift arm 230) is coupled to the front frame member 212 and the lift arm 230, and is operable to raise and lower the lift arm 230 under power. The front frame member 212 also supports front wheels 242A, 242B. Front wheels 242A, 242B are mounted to rigid axles (i.e., axles that do not pivot with respectto the front frame member 212). The cab 250 is also supported by the front frame member 212 so that, when the front frame member 212 articulates with respect to the rear frame member 214, the cab 250 moves with the front frame member 212 so that it will swing out to either side relative to the rear frame member 214, depending on which way the loader 200 is steered.

[0069] The rear frame member 214 supports various components of the power system 220, including a power source thereof (e.g., an internal combustion engine). In addition, one or more hydraulic pumps are coupled to the power source and supported by the rear frame member 214. The hydraulic pumps are part of a power conversion system to convert power from the power source into a form that can be used by actuators (such as cylinders and drive motors) on the loader 200. Power system 220 is discussed in more detail below. In addition, rear wheels 244 A, 244B are mounted to rigid axles that are in turn mounted to the rear frame member 214. When the loader 200 is steered in a straight direction (i.e., the front frame member 212 is aligned with the rear frame member 214), a portion of the cab 250 is positioned over the rear frame member 214.

[0070] The lift arm assembly 230 shown in FIGS. 2 and 3 is one example of many different types of lift arm assemblies that can be attached to a power machine, such as loader 200, or other power machines on which examples of the present discussion can be practiced. The lift arm assembly 230 is a radial lift arm assembly, in that the lift arm 230 is mounted to the frame 210 at one end of the lift arm assembly 230 and pivots about the articulation joint 216 as it is raised and lowered. The lift arm assembly 230 is also a telescoping lift arm, in that the lift arm assembly 230 includes a boom 232 that is pivotally mounted to the front frame member 212 at the articulation joint 216. A telescoping member 234 is slidably inserted into the boom 232 and a telescoping cylinder is coupled to the boom 232 and the telescoping member 234 and is operable to extend and retract the telescoping member 234 under power. The telescoping member 234 is shown in FIGS. 2 and 3 in a fully retracted position. The implement interface 270, including implement carrier 272 and power couplers 274, is operably coupled to the telescoping member 234. An implement carrier mounting structure 276 is mounted to the telescoping member 234. The implement carrier 272 and the power couplers 274 are mounted to the positioning structure. A tilt cylinder 278 is pivotally mounted to both the implement carrier mounting structure 276 and the implement carrier 272 and is operable to rotate the implement carrier 272 with respect to the implement carrier mounting structure 276 under power. Among the operator controls 260 in the operator station 255 (e.g., within an enclosedcompartment defined partly by the structure of the cab 250, as shown) are operator controls to allow an operator to control the lift, telescoping, and tilt functions of the lift arm assembly 230.

[0071] Other lift arm assemblies can have different geometries and can be coupled to the frame of a loader in various ways to provide lift paths that differ from the radial path of lift arm assembly 230. For example, some lift paths on other loaders provide a radial lift path. Others have multiple lift arms coupled together to operate as a lift arm assembly. Still other lift arm assemblies do not have a telescoping member. Others have multiple segments. Unless specifically stated otherwise, none of the inventive concepts set forth in this discussion are limited by the type or number of lift arm assemblies that are coupled to a particular power machine.

[0072] Frame 210 supports and generally encloses the power system 220 so that the various components of the power system 220 are not visible in FIGS. 2 and 3. FIG. 4 includes, among other things, a diagram of various components of an example configuration of the power system 220. Power system 220 includes one or more power sources 222 that are capable of generating or storing power for use on various machine functions. In some examples, the power system 220 includes an internal combustion engine. Other power machines, including those presented below, can include electric generators, rechargeable batteries, various other power sources or any combination of power sources that can provide power for given power machine components. The power system 220 also includes a power conversion system 224, which is operably coupled to the power source 222. Power conversion system 224 is, in turn, coupled to one or more actuators 226, which can perform a function on the loader 200.

[0073] Power conversion systems in various power machines can include various components, including mechanical transmissions, hydraulic systems, electrical control and transmission systems, and the like. For example, the power conversion system 224 of loader 200 includes a hydrostatic drive pump 224A, which provides a power signal to drive motors 226 A, 226B, 226C, 226D. The four drive motors 226 A, 226B, 226C, 226D in turn are each operably coupled to four axles 228A, 228B, 228C, 228D, respectively. The four axles 228A, 228B, 228C, 228D are coupled to the four wheels 242A, 242B, 244A, 244B, respectively. The hydrostatic drive pump 224A can be mechanically, hydraulically, or electrically coupled to operator input devices to receive actuation signals for controlling the drive pump 224A. The power conversion system 224 also includes an implement pump 224B, which is also driven by the power source 222. The implement pump 224B is configured to provide pressurized hydraulic fluid to a work actuator circuit 238. Work actuator circuit 238 is in communicationwith work actuator 239. Work actuator 239 is representative of a plurality of actuators, including the lift cylinder, tilt cylinder, telescoping cylinder, and the like. The work actuator circuit 238 can include valves and other devices to selectively provide pressurized hydraulic fluid to the various work actuators represented by block 239 in FIG. 4. In addition, the work actuator circuit 238 can be configured to provide pressurized hydraulic fluid to work actuators on an attached implement.

[0074] In some cases, a power conversion system of a power machine can include only two drive motors. For example, in the power conversion system 224 of the loader 200, the drive motor 226A can be operably coupled to both axles 228A, 228B that are coupled to the front wheels 242A, 242B, respectively, and the drive motor 226C can be operably coupled to both axles 228C, 228D that are coupled to the rear wheels 244A, 244B, respectively. Further, in some cases, the drive motors 226A, 226B, 226C, 226D can be configured to be electrically powered (such as, e.g., by the power source 222 or other electrical source of the loader 200).

[0075] The description of power machine 100 and loader 200 above is provided for illustrative purposes, to provide illustrative environments on which the examples discussed below can be practiced. While the examples discussed can be practiced on a power machine such as is generally described by the power machine 100 shown in the block diagram of FIG. 1 and more particularly on a loader, such as loader 200, unless otherwise noted or recited, the concepts discussed below are not intended to be limited in their application to the environments specifically described above.

[0076] Referring now to FIG. 5, an example frame of a power machine having a suspension system is shown, according to examples of the present disclosure. Power machine 300 of FIG. 5 is another particular example of the loader 200 illustrated broadly in FIGS. 2-4 (and the power machine of FIG. 1). To that end, features of power machine 300 described below include reference numbers that are generally similar to those used in FIGS. 2-4 and preceding discussion of particular components generally applies to similarly named and numbered components presented below. For example, power machine 300 is described as having a frame 310, just as loader 200 has the frame 210.

[0077] Similar to the frame 210 of the loader 200, the frame 310 also includes a front frame member 312 and a rear frame member 314. The rear frame member 314 is pivotally coupled to the front frame member 312 at an articulation frame joint 316 and is correspondingly pivotable about a pivot axis 317 (e.g., a vertical axis, as shown in FIG. 5). Moreover, the power machine300 further includes a suspension system 380 that is operably coupled with a traction system 340 of the power machine 300. In particular, the suspension system 380 can be configured to support one or more axle assemblies of the traction system 340 relative to the frame 310, such as, e.g., a first rear axle assembly, a second rear axle assembly 328D of the rear frame member 314, a first front axle assembly, or a second front axle assembly 328B. In some cases, the traction system 340 can include two or more suspension assemblies that can independently support one or more axle assemblies of the traction system 340c. In some cases, a suspension assembly can support two axles non-independently - e.g., with a rigid connection for the suspension between axles on opposing lateral sides of a frame).

[0078] Referring still to FIG. 5, in the illustrated example, the suspension system 380 includes at least one suspension member 386. The suspension member 386 is supported by the frame 310 (e.g., the front or rear frame member 312, 314) and operably engaged to one or more of the relevant axle assemblies of the tractive system 340 (e.g., axle assemblies 328B, 328D). In this regard, some example suspension members can be configured according to various known suspension designs. Accordingly, in some cases, the suspension member 386 can be one or more of a variety of components that operably engage one or more of the axle assemblies of the power machine 300 to provide suspension support. For example, in some cases, the suspension member 386 can be a torsion member (e.g., a torsion bar, as further discussed below), a spring member (e.g., a coil spring or a leaf spring), or a gas bag.

[0079] Referring now to FIGS. 6-8, another example configuration of the suspension system 380 of the power machine 300 is shown, according to examples of the present disclosure. Power machine 300 of FIGS. 6-8 is another particular example of the loader 200 illustrated broadly in FIGS. 2-4 (and the power machine of FIG. 1) and of the suspension system 380 of power machine 300 in FIG. 5. To that end, features of power machine 300 described below include reference numbers that are generally similar to those used in FIGS. 2-5 and preceding discussion of particular components generally applies to similarly named and numbered components presented below. For example, power machine 300 is described as having a frame 310 and a power system 320, just as loader 200 has the frame 210 and the power system 320.

[0080] Similar to the frame 210 of the loader 200, the frame 310 also includes a front frame member 312 and a rear frame member 314 that is pivotally coupled to the front frame member 312 at an articulation frame joint 316 and pivotable about a pivot axis 317 (e.g., a vertical axis, as shown in FIG. 5). In this regard, in a default (e.g., zero-pivot) orientation, a front-to-back direction of the power machine overall, as shown with dot-dash arrows in FIG. 6, may alignwith front-to-back directions of each of the frame members 312, 314, as shown with dash-dash arrows in FIG. 6. However, when the frame members 312, 314 are pivoted away from a default orientation (e.g., to non-zero pivot), a front-to-back direction of the front frame member 312 may no longer align with a front-to-back direction of the rear frame member 314. As a general reference frame, a front-to-back direction for a particular frame member can extend in a horizontal plane, perpendicular to a rotational axis of an axle supported by the frame member (e.g., a fixed-direction rotational axis for a fixed axle, or a rotational axis at a zero-turn orientation of a steerable axle).

[0081] Referring to FIG. 6 in particular, and further similar to the frame 210 of the loader 200, the frame 310 of the power machine 300 supports the power system 320, a lift arm assembly 330, and a traction system 340 of the power machine 300. In particular, the front frame member 312 supports the lift arm assembly 330 and a cab 350 while the rear frame member 314 supports various components of the power system 320, including a power source 322 thereof (such as, e.g., an internal combustion engine).

[0082] Referring to FIG. 7 in particular, the traction system 340 of the power machine 300 is powered by the power system 320 and can propel the power machine 300 over a support surface. In the illustrated example, the traction system 340 includes four separate axle assemblies, to support and power four separate ground-engaging elements, although other configurations (e.g., numbers of axle assemblies) are possible.

[0083] More specifically, in the illustrated example, a first front wheel 342A and a second front wheel 342B are supported by the front frame member 312 and a first rear wheel 344A and a second rear wheel 344B are supported by the rear frame member 314. Correspondingly, the power system 320 of the power machine 300 includes a first front drive motor 326A, a second front drive motor 326B, a first rear drive motor 326C, and a second rear drive motor 326D that are operably coupled to a first front axle assembly 328A, a second front axle assembly 328B, a first rear axle assembly 328C, and a second rear axle assembly 328D, respectively. The axle assemblies 328A-D are in turn operably coupled to the wheels 342A, 342B, 344A, 344B, respectively, of the traction system 340. As such, the drive motors 326A- D can be powered independently to cause rotation of axles of the respective axle assemblies 328A-D, which results in rotation of the respective wheels 342A, 342B, 344A, 344B.

[0084] In some cases, the drive motors 326A-D can be hydraulically powered by one or more drive pumps of the power system 320. In other cases, the drive motors 326A-D can beelectrically powered by the power source 322 of the power system 320. In some cases, the traction system 340 can include tractive elements other than the wheels 342A, 342B, 344A, 344B, such as, e.g., independent track assemblies.

[0085] As mentioned above, examples of the disclosed technology can provide a suspension system that can counteract forces transmitted to the frame by a traction system, and thereby generally improve driving experience for an operator of the power machine. For example, with continued reference to FIG. 7, power machine 300 further includes a suspension system 380 that is operably coupled with the traction system 340. In particular, the suspension system 380 of power machine 300 includes a front suspension assembly 382A that is supported by the front frame member 312 and a rear suspension assembly 382B that is supported by the rear frame member 314. The front suspension assembly 382A is operably coupled to the front axle assemblies 328A, 328B, to support the front wheels 342A, 342B relative to the front frame member 312 and transmit forces from ground-engagement between the front wheels 342A and the front frame member 312. The rear suspension assembly 382B is similarly operably coupled to the rear frame member 314, to support the rear axle assemblies 328C, 328D and transmit to the rear frame member 314 forces from the rear wheels 344A, 344B.

[0086] Generally, front and rear suspension assemblies according to the disclosed technology can include cantilevered arms or other lever members that support corresponding axle assemblies, and torsion members that connect the lever members to a corresponding part of the power machine frame. In this regard, and as further discussed below, a torsion member can take a variety of forms, including known torsion tube configurations, and can be secured to a frame in a variety of ways. Similarly, a variety of lever members, appropriately sized and secured, can be used to support a variety of axle assemblies.

[0087] In particular, for the illustrated example, the front suspension assembly 382A of the suspension system 380 includes a front suspension housing 384 A, a first front torsion member 386A, a second front torsion member 386B, a first front suspension arm 388 A, and a second front suspension arm 388B. The first and second front torsion members 386A, 386B are at least partly contained within the front suspension housing 384 A and are secured thereby to the front frame member 312. The first front suspension arm 388A is operably coupled to the first front torsion member 386A at one end and the first front axle assembly 328 A at the other end, and the second front suspension arm 388B is operably coupled to the second front torsion member 386B at one end and the second front axle assembly 328B at the other end. Thus, in particular, the front suspension arm 388 A cantilevers the first front axle assembly 328 A relative to thefirst front torsion member 386A (and thereby the front frame member 312), and the second front suspension arm 388B cantilevers the second front axle assembly 328B relative to the second front torsion member 386B (and thereby the front frame member 312).

[0088] Likewise, the rear suspension assembly 382B of the suspension system 380 includes a rear suspension housing 384B, a first rear torsion member 386C, a second rear torsion member 386D, a first rear suspension arm 388C, and a second rear suspension arm 388D. The first and second rear torsion members 386C, 386D are at least partly contained within the rear suspension housing 384B and are secured thereby to the rear frame member 314. The first rear suspension arm 388C is operably coupled to the first rear torsion member 386C at one end and the first rear axle assembly 328C at the other end, and the second rear suspension arm 388D is operably coupled to the second rear torsion member 386D at one end and the second rear axle assembly 328D at the other end. Thus, in particular, the rear suspension arm 388C cantilevers the first rear axle assembly 328C relative to the first rear torsion member 386C (and thereby the rear frame member 314), and the second rear suspension arm 388D cantilevers the second rear axle assembly 328D relative to the second rear torsion member 386D (and thereby the rear frame member 314).

[0089] Generally, the torsion members 386A-D can be configured as tubes or other beams that can resiliently react to torsional forces exerted thereon. Thus, the torsion members 386A- D can be rotationally moved in response to torsion during operation of the power machine 300, then resiliently return to a default (e.g., undeformed) configuration as the torsional force is reduced or removed. In some cases, the torsion members 386A-D can be tubes or other hollow beams (e.g., square tubes as shown in FIG. 8). In some cases, the torsion members 386A-D can be included in larger torsion assemblies, which can also include additional elastic components to support a resilient response to torsional forces. For example, as also discussed below, rubber pads can be included, to interact with a corresponding tube (or other torsion member) to provide a resilient response to a torsional force.

[0090] As shown in FIG. 7 in particular, relative to a front-to-back direction, the front suspension assembly 382A is secured to the front frame member 312 behind the front axle assemblies 328A, 328B and between the front axle assemblies 328A, 328B and the rear axle assemblies 328C, 328D. Similarly, the rear suspension assembly 382B is secured to the rear frame member 314 ahead of the rear axle assemblies 328C, 328D and between the rear axle assemblies 328C, 328D and the front axle assemblies 328 A, 328B. Correspondingly, in the illustrated example, the front suspension arms 388 A, 388B extend forward to support the axleassemblies 328 A, 238B, and the rear suspension arms 388C, 388D extend rearward to support the axle assemblies 328C, 328D.

[0091] This general arrangement of either (or both) of the suspension assemblies 382A, 382B, relative to the corresponding axle assemblies 328A-D can provide improved dynamic load stability while the power machine 300 is operated to travel along a ground surface. For example, when the power machine 300 accelerates in a forward direction (as indicated by arrow 390 in FIG. 8), the weight of the power machine 300 shifts toward the rear wheels 344 A, 344B. This can cause the rear axle assemblies 328C, 328D to move upward relative to the rear frame member 314 (i.e., in the direction indicated by arrow 394B in FIG. 8), and can simultaneously cause the front axle assemblies 328A, 328B move downward relative to the front frame member 312 (i.e., in the direction indicated by arrow 396A in FIG. 8). In this regard, the suspension arms 388A-D can generally allow independent vertical movement of the corresponding wheels 344A-D (e.g., as a component of a generally circumferential movement of the arm 388A-D about a center defined by the torsion members 386A-D).

[0092] Such upward movement of the rear axle assemblies 328C, 328D is translated to the respective rear torsion members 386C, 386D via the rear suspension arms 388C, 388D and applies a torsional force to the rear torsion members 386C, 386D in a first rotational direction. The counteractive force from the rear torsion members 386C, 386D thus urges the rear axle assemblies 328C, 328D in a downward direction (i.e., in the direction indicated by arrow 396B in FIG. 8). Similarly, such downward movement of the front axle assemblies 328A, 328B is translated to the respective front torsion members 386 A, 386B via the front suspension arms 388 A, 388B and applies a torsional force to the front torsion members 386A, 386B in a second rotational direction that is opposite the first rotational direction. The counteractive force from the front torsion members 386A, 386B thus urges the front axle assemblies 328 A, 328B in an upward direction (i.e., in the direction indicated by arrow 394A in FIG. 8). In other words, the suspension system 380 can help to reduce (e.g., prevent) “squatting” of the power machine 300 (i.e., over-rotation of the frame 310 toward the rear) when the power machine 300 accelerates in the forward direction 390.

[0093] Similarly, when the power machine 300 is braked from forward movement (i.e., via braking force in the direction indicated by the arrow 392 in FIG. 8), the weight of the power machine 300 shifts toward the front wheels 342A, 342B. This can cause the front axle assemblies 328A, 328B to move upward relative to the front frame member 312 (i.e., in the direction indicated by arrow 394 A in FIG. 8), and simultaneously can cause the rear axleassemblies 328C, 328D to move downward relative to the rear frame member 314 (i.e., in the direction indicated by arrow 396B in FIG. 8).

[0094] Such upward movement of the front axle assemblies 328A, 328B is translated to the respective front torsion members 386A, 386B via the front suspension arms 388 A, 388B and applies a torsional force to the front torsion members 386 A, 386B in a second rotational direction opposite the first rotational direction. The counteractive force from the front torsion members 386A, 386B thus urges the front axle assemblies 328 A, 328B in a downward direction (i.e., in the direction indicated by arrow 396A in FIG. 8). Similarly, such downward movement of the rear axle assemblies 328C, 328D is translated to the respective rear torsion members 386C, 386D via the rear suspension arms 388C, 388D and applies a torsional force to the rear torsion members 386C, 386D in a first rotational direction that is opposite the second rotational direction. The counteractive force from the rear torsion members 386C, 386D thus urges the rear axle assemblies 328C, 328D in an upward direction (i.e., in the direction indicated by arrow 394B in FIG. 8). In other words, the suspension system 380 can help to reduce (e.g., prevent) “diving” of the power machine 300 (i.e., over-rotation of the frame 310 toward the front) when the power machine 300 is braked.

[0095] As mentioned above, the front and rear suspension assemblies 382 A, 382B of the suspension system 380 are configured to interact with forces transmitted to the front and rear frame members 312, 314, respectively. For example, in some cases, the torsion members 386A- D can be configured to resist upward and downward motion of the respective axle assemblies 328 A-D relative to the frame 310 (e.g., by a resilient, torsional resistance) and thus can provide the dynamic load stability features described above (i.e., anti-squat and anti-dive) as well as automatic leveling of the power machine 300. Accordingly, in some such cases, the suspension system 380 can be configured such that a leveling or clearance height of the power machine 300 (i.e., a height of the frame 310 relative to a ground surface) can be adjustable by an operator by adjusting the front and rear suspension assemblies 382A, 382B.

[0096] Further, in the illustrated example, the suspension system 380 of the power machine 300 is configured as a semi-independent suspension system, in that the front suspension assembly 382 A can respond to movement of the frame 310 independently of the rear suspension system 382B. In some cases, the suspension system 380 can be configured as a fully independent suspension system, in which the axle assemblies 328A-D can move relative to the frame 310 independent from the others. In this regard, one or both of the front and rear suspension assemblies 382 A, 382B can be configured so that the torsion members 386 A-D areindependent from the others. Accordingly, such a fully independent suspension system can permit the suspension for each wheel 342A, 342B, 344A, 344B to respond independent from the others, which can provide a smoother ride, less sway, reduced noise, and increased life of components of the suspension system 380. In some cases, however, as also further discussed below, torsion members on opposing sides of a power machine can be tied together. For example, the torsion members 386A, 386B (or 386C, 38D) can be mechanically tied together so that rotation of one of the members 386 A, 386B causes at least some rotation in the other. Such an arrangement, for example, can provide for improved performance during turning travel.

[0097] In some example, the suspension system 380 may include damping systems or be otherwise generally configured to provide dampening forces relative to movement of the axle assemblies 328A-D relative to the frame 310. Such a configurations, for example, can further contribute to a smooth ride of the power machine 300 and help prevent over-oscillation of the frame 310 in response to travel over a particularly rough ground surface.

[0098] For example, with reference again to FIG. 8, one or both of the front and rear suspension assemblies 382 A, 382B can include a dampening member 398 (indicated as dashed boxes in FIG. 8) that can be operably coupled to one of the suspension arms 388A-D and the respective one of the front or rear frame member 312, 314. As such the one or more dampening members 398 may be arranged to dampen movement of the suspension arms 388A-D, and help reduce transmission of vibrations between the suspension arms 388A-D and the front and rear frame members 312, 314. Generally, the dampening member(s) 398 can be any of various components known in the art that can mechanically or fluidically dampen movement of a corresponding lever member (e.g., any of the suspension arms 388A-D). For example, in some cases, a dampening member can be an oil- or gas-based shock absorber of various known configurations. In some cases, a dampening member can be included in a torsion assembly (e.g., along with one or more of the torsion members 386A-D).

[0099] It should be appreciated that other configurations of a suspension system of a power machine may provide the benefits discussed above along with providing minimal added weight and size requirements for the power machine. In that regard, FIGS. 9-18 illustrate another example of a suspension system 480 that can be used with the power machine 300 of FIG. 3 (e.g., as an alternative configuration of the suspension systems 380, etc.). As will be recognized, the suspension system 480 shares a number of components in common with and operates in a similar fashion to the examples illustrated and described previously. For the sakeof brevity, these common features will not be described again below in detail. Rather, previous discussion of similarly named or numbered features, unless otherwise indicated, also applies to example configurations of the suspension system 480.

[0100] In some examples, the suspension system 480 is described as having a front suspension assembly 482A and a rear suspension assembly 482B, just as the suspension system 380 has the first and rear suspension assemblies 382A, 382B. Correspondingly, discussion above of the suspension system 380 and of the power machines 100, 200, 300 generally also applies relative to the example of FIGS. 9-18.

[0101] As mentioned above, the suspension system 480 of FIGS. 9-18 is similar in many aspects to the suspension system 380 of FIGS. 6-8. For example, the suspension system 480 of power machine 300 includes the front suspension assembly 482A that is supported by the front frame member 312 and is operably coupled to the front axle assemblies 328A, 328B and the rear suspension assembly 482B that is supported by the rear frame member 314 and is operably coupled to the rear axle assemblies 328C, 328D. The front suspension assembly 482A of the suspension system 480 includes a front suspension housing 484A, a first front torsion member 486A, a second front torsion member 486B, a first front suspension arm 488A, and a second front suspension arm 488B. The first front suspension arm 488A is operably coupled to the first front torsion member 486A at one end and the first front axle assembly 328A at the other end, and the second front suspension arm 488B is operably coupled to the second front torsion member 486B at one end and the second front axle assembly 328B at the other end. Likewise, the rear suspension assembly 482B of the suspension system 480 includes a rear suspension housing 484B, a first rear torsion member 486C, a second rear torsion member 486D, a first rear suspension arm 488C, and a second rear suspension arm 488D. The first rear suspension arm 488C is operably coupled to the first rear torsion member 486C at one end and the first rear axle assembly 328C at the other end, and the second rear suspension arm 488D is operably coupled to the second rear torsion member 486D at one end and the second rear axle assembly 328D at the other end.

[0102] However, in some aspects the suspension system 480 of FIGS. 9-18 differs from the suspension system 380 of FIGS. 6-7. For example, as shown in FIGS. 11 and 13 in particular, the first and second suspension assemblies 482A, 482B of the suspension system 480 are arranged at a shorter (front-to-back) spacing from the front axle assemblies 328A, 328B and the rear axle assemblies 328C, 328D, respectively, in comparison to the suspension system 380 shown in FIGS. 6-8. Such an arrangement of the suspension assemblies 482 A, 482B relativeto the axle assemblies 328A, 328B, 328C, 328D can help to reduce torsional forces applied by the suspension arms 488A-D and thus prevent excessive bending of the suspension arms 488A- D or allow for a reduced weight thereof.

[0103] The suspension system 480 also includes differently configured lever members. As shown in FIGS. 14 and 15 in particular, each of the suspension arms 488A-D of the suspension system 480 includes an axle opening 504 at which the axle assemblies 328A-D are mounted to extend both inboard and outboard of the respective suspension arm 488A-D. In other examples, other arrangements can be used to secure axle assemblies to lever members (e.g., to any of the suspension arms 488A-D).

[0104] Corresponding openings on the frame 310 can also be provided, to receive and accommodate movement of the respective drive motors or other components of the axel assemblies 328A-D. In this regard, the frame 310 of FIGS. 9-18 is somewhat modified relative to the example configuration shown in FIGS. 5-8. For example, extension (and reinforcement) plates 502A, 502B, 502C, 502D can be provided on the front and rear frame members 312, 314, respectively, to ensure appropriate frame strength and dimensions at the openings for the axle assemblies 328A-D.

[0105] It should be appreciated that, in some cases, the frame 310 of the power machine 300 can be configured differently than as shown in FIGS. 9-18, and, in such cases, the suspension assemblies 482 A, 482B of the suspension system 480 can be coupled to the frame 310 without the use of the extension plates 502A-D. For example, in some cases, the extension plates 502A- D can be integrally formed with the respective front and rear frame members 312, 314 of the frame 310.

[0106] In some cases, a suspension assembly of a suspension system can be configured to permit a predetermined travel of an axle relative to the frame, such as, e.g., to prevent damage to the frame or components of the suspension system. For example, referring to FIG. 13 in particular, the extension plates 502A-D include a first (i.e., upper) protrusion 508 and a second (i.e., lower) protrusion 510 that extend laterally outward from the frame 310. The upper protrusions 508 are configured to prevent movement of the suspension arms 488A-D in an upwardly vertical direction (e.g., in the directions 394A, 394B shown in FIG. 8), and the lower protrusions 510 are configured to prevent movement of the suspension arms 488 A-D in a downwardly vertical direction (e.g., in the directions 396A, 396B shown in FIG. 8). In some cases, the upper and lower protrusions 508, 510 can be adjustable by an operator.

[0107] With or without the protrusions 508, 510 or other stops, the suspension system 480 (and others disclosed herein) can provide a relatively high level of suspension performance while also maintaining a relatively low lateral footprint. For example, as shown in FIG. 12 in particular, the arrangement of front and rear suspension assemblies 482A, 482B of the suspension system 480 on the frame 310 requires relatively minimal space laterally outboard of the frame 310. This may provide for a reduced overall size and weight of the power machine 300 in comparison to conventional suspension systems, and allow for corresponding efficiencies in manufacturing an operation.

[0108] In some cases, a suspension assembly of a suspension system can include additional components or structures to reduce bending of a lever member of the suspension assembly. For example, other mechanical guide structures can be provided to limit inboard or outboard deflection of lever members. In this regard, in the illustrated configuration of the suspension system 480, the suspension assemblies 482A, 482B further include inboard support members 512 disposed between the suspension arms 488A-D and the frame 310 (e.g., at the extension plates 502A-D). More specifically, the inboard support members 512 are arranged contact end portions 514 of the suspension arms 488A-D that extend past the respective axle assemblies 328A, 328B, 328C, 328D opposite the respective torsion members 486A-D. In some cases, the inboard support members 512 can be a compressible pad or can be otherwise configured to provide reduced friction between the pad and the suspension arms 488A-D during continued operation of the power machine 300.

[0109] Such an arrangement of the inboard support member 512 and the extension portions 514 can provide a support surface for the suspension arms 488A-D and thereby help to prevent the suspension arms 488A-D from excessive deflection in an inboard direction relative to the frame 310 (i.e., “toeing in”). As such, inclusion of the inboard support members 512 may allow for less rigidity of the suspension arms 488A-D, which may provide for reduced weight of the suspension arms 488A-D and of the power machine 300.

[0110] Relatedly, in some case, one or both of the suspension assemblies 482A, 482B of the suspension system 480 can include other guide structures to help prevent unwanted deflection of the suspension arms 488A-D. In some cases, brackets or other structures can be provided to help prevent excessive deflection of the suspension arms 488A-D in an outboard direction relative to the frame 310 (i.e., “toeing out”). For example, as shown in FIG. 13, one or both of the suspension assemblies 482 A, 482B can further include an outboard support member 516 that can engage an outer surface of the extension portions 514 of the suspension arms 488 A-Dopposite the inboard support members 512. In some cases, the outboard support members 516 may be a bracket (e.g., a U-shaped bracket) that is attached (e.g., fixedly or integrally formed with) the extension plates 502A, 502B, 502C, 502D or the frame 310 and that can permit movement of the extension portions 514 therewithin while maintaining contact with the extension portions 514. Similar to the inboard support members 512, inclusion the outboard support members 516 may all for less rigidity of the suspension arms 488A-D, which can provide for further reduced weight of the suspension arms 488A-D and the power machine 300.

[0111] As also noted above, torsion members in the disclosed suspensions can be secured to corresponding power machine frames in a variety of ways. As shown in FIGS. 16 and 17 in particular, in some cases, one or both of the suspension housings 484A, 484B of the suspension system 480 can be formed of a first (e.g., inner) housing portion 520 that is coupled to the frame 310 and a second (e.g., outer) housing portion 522 that is coupled to the inner housing portion 520. Such a configuration of one or both of the suspension housings 484A, 484B can provide ease of disassembly of the housings 484A, 484B and maintenance of the suspension system 480.

[0112] In some cases, the inner housing portion 520 of one or both of the suspension housings 484A, 484B can be integrally formed with the frame 310. Further, as shown in FIGS. 10 and 11 in particular, in some cases, the frame 310 can include one or more skid plates 526 that can be attached to (e.g., fixedly to or integrally formed with) one or both of the front and rear frame members 312, 314 adjacent to the front and rear suspension assemblies 382A, 382B. The skid plates 526 may be configured to prevent damage to the suspension housings 484A, 484B by objects or debris along a ground surface over which the power machine 300 travels.

[0113] As mentioned above, torsion assemblies of a suspension system of a power machine can be configured to provide dynamic load stability features by resiliently responding to motion of an axle relative to a frame. In an example configuration, with reference to FIG. 17 in particular, one or more of the torsion members 486A-D of the suspension system 480 can be formed as a hollow torsion beam 530 that is coupled to the respective suspension arm 488A-D and that engages one or more elastomeric (e.g., rubber) torsion pads 532 within the corresponding housing 484A, 484B. Thus, the resilient response of the torsion pads 532 can provide a resilient response of the suspension overall, as the torsion beam 530 is subjected to torsional force.

[0114] In the illustrated example, the torsion beam 530 has a square shaped cross sectional shape, arranged at a rotational offset of 45-degrees relative to the housing 484A. Further, four of the elastomeric pads 532 are arranged within the suspension housing 484A, 484B along each outer side of the torsion beam 530. In other examples, the torsion beam 530, the housing 484A, or the torsion pads 532 can have other cross-sectional shapes or relative orientations, and can be formed from various elastomer (or other) materials. Similarly, in other examples, other generally known structures can be used to provide similar torsional response for the torsion beam 530 relative to a frame (e.g., with different numbers or shapes of elastomeric members, different mounting structures relative to a frame, etc.).

[0115] As also mentioned above, a suspension system of a power machine can be configured as a fully independent suspension system, in that each axle can move independent of any other axles. For example, with reference to FIGS. 15 and 16 in particular, at least the front suspension assembly 482A of the suspension system 480 is configured such that the first front torsion member 486A is independent of the second front torsion member 486B. More specifically, a gap 540 is formed between an inner end of the torsion beam 530 of the first front torsion member 486A and an inner end of the torsion beam 530 of the second front torsion member 486B. In other words, the torsion beams 530 of the first and second front torsion members 486A, 486B are not connected directly together, and the one torsion beam 530 can move independently of the other torsion beam 530. In some cases, the rear suspension assembly 482A can be configured similar to the front suspension assembly 482B. In other cases, the torsion beams 530 of one or both of the front and rear suspension assemblies 482A, 482B may be connected. For example, material may bridge (e.g., eliminate) the gap 540 in some configurations so that torsion on one of the torsion beams 530 is directly, mechanically transmitted to the other torsion beam 530.

[0116] It should be appreciated that other configurations of a suspension system of a power machine may provide some of the benefits discussed above as well as additional benefits. In this regard, FIG. 22 illustrates another example of a suspension system 680 that can be used with the power machine 300 of FIG. 3 (e.g., as an alternative configuration of the suspension systems 480, etc.). As will be recognized, the suspension system 480 shares a number of components in common with and operates in a similar fashion to the examples illustrated and described previously. For the sake of brevity, these common features will not be described again below in detail. Rather, previous discussion of similarly named or numbered features,unless otherwise indicated, also applies to example configurations of the suspension system 480.

[0117] In some examples, suspension system 680 is described as having a front suspension assembly 682A and a rear suspension assembly 682B, just as the suspension systems 380, 480 have the first and rear suspension assemblies 382A, 382B, 482A, 482B. Correspondingly, discussion above of the suspension systems 380, 480 and of the power machines 100, 200, 300 generally also applies relative to the example of FIG. 22.

[0118] As mentioned above, the suspension system 680 of FIG. 22 is similar in many aspects to the suspension system 480 of FIGS. 9-18. For example, the suspension system 680 of power machine 300 includes the front suspension assembly 682A that is supported by the front frame member 312 and is operably coupled to the front axle assemblies 328A, 328B and the rear suspension assembly 682B that is supported by the rear frame member 314 and is operably coupled to the rear axle assemblies 328C, 328D. The front suspension assembly 682A of the suspension system 680 includes a front suspension housing, a first front torsion member, a second front torsion member 686B, a first front suspension arm, and a second front suspension arm 688B, which are assembled to function similar to the front suspension assembly 482A of the suspension system 480 of FIGS. 9-18. Likewise, the rear suspension assembly 682B of the suspension system 680 includes a rear suspension housing, a first rear torsion member, a second rear torsion member 686D, a first rear suspension arm, and a second rear suspension arm 688D, which are assembled to provide function similar to the rear suspension assembly 482B of the suspension system 480 of FIGS. 9-18.

[0119] However, in some aspects the suspension system 680 of FIG. 22 differs from the suspension system 480 of FIGS. 9-18. For example, as shown in FIG. 22, relative to a front-to- back direction, the rear suspension assembly 682B is secured to the rear frame member 314 behind the rear axle assemblies 328C, 328D and between the rear axle assemblies 328C, 328D and a rear end of the rear frame member 314. Correspondingly, in the illustrated example, the first rear suspension arm and the second rear suspension arm 688D extend forward to support the rear axle assemblies 328C, 328D. In addition, the first front suspension arm and the second front suspension arm 688B extend similarly forward to support the front axle assemblies 328A, 328B. This particular arrangement of the suspension assemblies 682A, 682B can further help to reduce (e.g., prevent) “squatting” of the power machine 300 when the power machine 300 accelerates in the forward direction 390 (see FIG. 7).

[0120] Additionally, as shown in FIG. 22, at least the first suspension assembly 682A of the suspension system 680 includes a guide structure that differs from that of the first suspension assembly 482A of the suspension system 480. For example, as shown in FIG. 22, the front suspension arm 688B includes a slot 750 at an end of the suspension arm 688B opposite the front torsion member 686B, such that the axle assembly 328B is located along the suspension arm 688B between the torsion member 686B and the slot 750. In addition, a front extension plate 702B of the first suspension assembly 682A includes a protrusion that is received within the slot 750 of the front suspension arm 688B, and thus the protrusion of the extension plate 702B can engage end portions of the slot 750 to provide stops on movement of the suspension arm 688B similarly to the protrusions 508, 510 of the suspension system 480 (see, e.g., FIG. 14).

[0121] Further, in the illustrated embodiment, an outboard support member 716 can be coupled to the protrusion of the extension plate 702B. The outboard support member 716 can thus slidably engage an outer surface of the suspension arm 688B, to function similar to the outboard support member 516 of the suspension system 480 (see FIG. 13). Accordingly, this guide structure of the first suspension assembly 682A of the suspension system 680 can reduce complexity of the suspension system 680 while further reducing wear to the components thereof during continued operation of the power machine 300. In some cases, the rear suspension assembly 682B of the suspension system 680 can include a guide structure similar to the guide structure of the front suspension assembly 682B, or either of the suspension assemblies 682A, 682B can include guide structures as otherwise discussed above.

[0122] FIGS. 23-31 illustrate another example of a suspension system 880 that can be used with the power machine 300 of FIG. 3 (e.g., as an alternative configuration of the suspension systems 480, 680, etc.). As will be recognized, the suspension system 880 shares a number of components in common with and operates in a similar fashion to the examples illustrated and described previously. For the sake of brevity, these common features will not be described again below in detail. Rather, previous discussion of similarly named or numbered features, unless otherwise indicated, also applies to example configurations of the suspension system 880.

[0123] In some examples, a frame 810 of the power machine may include a front frame member 812 and a rear frame member 814. The rear frame member 814 may be pivotally coupled to the front frame member 812 at an articulation frame joint 816 and may be correspondingly pivotable about a pivot axis formed by the frame joint 816 (e.g., a verticalaxis, as shown in FIG. 5). In some examples, the power machine further includes a suspension system 880 that is operably coupled with the traction system of the power machine. In particular, the suspension system 880 can be configured to support one or more axle assemblies of the traction system relative to the frame 810. In some cases, the traction system can include one or more suspension assemblies that can independently support one or more axle assemblies of the traction system. For example, referring in particular to FIG. 36, the power machine may include four suspension assemblies, with a first suspension assembly 882A corresponding to a first axle assembly 328A, a second suspension assembly 882B corresponding to a second axle assembly 328B, a third suspension assembly 882C corresponding to a third axle assembly 328C, and a fourth suspension assembly 882D corresponding to a fourth axle assembly 328D. Thus, in some examples, the suspension system 880 may provide an independent suspension system for each of the wheels (or other ground engaging elements) supported by the axles, which may significantly increase operator comfort during operation of the power machine.

[0124] Referring in particular to FIGS. 25-27, in some examples, each (or some) of the suspension assemblies 882A-882D may include a first weldment 902 and a second weldment 904. The first weldment 902 may include a suspension housing 884 with a flange 912 at a first end and a removable (or other) end cap 914 at a second, opposite end. In some examples, the first weldment 902 may be positioned within a portion of the frame 810 by sliding the suspension housing 884 through an opening 906 of the frame 810. In some cases, the dimensions of the opening 906 may correspond to the dimensions of the suspension housing 884. For example, the suspension housing 884 nay define a rectangular shape, while the opening 906 may correspondingly define a (slightly larger) rectangular shape.

[0125] Following the insertion of the suspension housing through the opening, the first weldment 902 may be secured to the frame 810 via one or more fasteners arranged through the flange 912 of the first weldment 902 into the frame 810. In some examples, to further secure the first weldment 902 in position, one or more fasteners may be arranged through the end cap 914 of the suspension housing 884. In other examples, the first weldment 902 may be secured to the frame 810 via only the fasteners arranged through the flange 912.

[0126] In some examples, the second weldment 904 may be configured to mount at least partially within the first weldment 902 (e.g., within the suspension housing) and may include suspension arm configured as a mounting plate 996 (or other lever member) and a torsion member 986. As shown in FIG. 26 in particular, the mounting plate 990 may define an opening 998 configured to receive and secure the axle assembly 328 (e.g., including an integrated motor226). Correspondingly, the torsion member 986 may be extend away from a face 1002 of the mounting plate 996. In some examples, the torsion member 986 may be welded to the face 1002. In other examples, the torsion member 986 may extend through the mounting plate 996 and be secured via one or more welds (or other fasteners) at a second, opposite face of the mounting plate.

[0127] In some examples, as mentioned above, the torsion member 986 may be at least partly contained (e.g., telescopically received) within the suspension housing 884. For example, as shown in FIG. 29, the torsion member 986 may extend within a channel 1004 defined by the suspension housing 884. In some examples, one or more elastomeric (e.g., rubber) torsion pads 1032 or other resilient (e.g., elastomer) inserts may be positioned within the channel 1004. Such inserts may engage the torsion member 986 within the channel 1004 to provide a resilient response of the suspension overall, as the torsion member 986 is subjected to torsional force. Thus, by resiliently resisting rotation of the torsion member 986, the torsion pads 1032 can resiliently resist vertical movement of the axle assembly 328 to provide improved handling and reduced harshness during operation of the power machine 300.

[0128] In some examples, the torsion member may be in the form of a torsion beam, which may have a rectangular (e.g., square) cross-sectional shape, arranged at a rotational offset relative to the housing 884 (e.g., a rotational offset of about 45 degrees, as shown in FIG. 29). Further, in some examples, four of the elastomeric pads 1032 may be arranged within the suspension housing 884 - e.g., along each outer side of the torsion beam. For example, the torsion pads 1032 may extend along an entire length of the torsion member (e.g., extend along an entire length of the suspension housing 884). In some examples, an alternative number, size, or shape of elastomeric pads 1032 may be used. Further, in other examples, the torsion beam, the housing, or the torsion pads can have other cross-sectional shapes or relative orientations, and can be formed from various elastomeric (or other) materials. Similarly, in other examples, other generally known structures can be used to provide similar torsional response for the torsion beam relative to a frame (e.g., with different numbers or shapes of elastomeric members, different mounting structures relative to a frame, etc.).

[0129] In some examples, the suspension housing 884 may be used to secure the second weldment 904, and thus the axle assembly 328 to the frame 810. For example, during manufacturing, once the first weldment 902 has been secured to the frame 810, the second weldment 904 may be secured to the first weldment 902. For example, the torsion member 986 may be positioned within the channel 1004 of the suspension housing 884. In some examples,prior to inserting the torsion member 986 into the channel 1004, the torsion pads 1032 may be arranged within the channel 1004 (e.g., in each of the four comers of the channel 1004 defied by the suspension housing 884). Thus, once the torsion member 986 is positioned within the suspension housing 884, the second weldment 904 may be secured to the first weldment 902 via the frictional force generated between the torsion pads 1032 and the torsion member 986, without the need for additional fasteners.

[0130] In some cases, the suspension system 880 can be configured as a fully independent suspension system, in which each of the axle assemblies 328A-D can move relative to the frame 810 independent from each other. In this regard, the suspension assemblies 882A-D can be configured so that the torsion members 986 A-D are independent from the others. For example, as shown in FIG. 25, the suspension assemblies 882A, 882B are on opposite lateral sides of the power machine 300, with the weldments 902 secured to the frame (not shown in FIG. 25) separately from each other (e.g., laterally spaced apart, as shown). In some examples, such a fully independent suspension system can accordingly permit the suspension for each wheel 342A, 342B, 344A, 344B to respond independently from the others, which can provide a smoother ride, less sway, reduced noise, and increased life of components of the suspension system 880.

[0131] In some cases, however, as also further discussed below, torsion members on opposing sides of a power machine can be tied together. For example, the torsion members 986A, 986B (or 986C, 986D) can be mechanically tied together so that rotation of one of the torsion members causes at least some rotation in the other. For example, a sleeve or other mechanical connector may be arranged through the torsion member 986A and the torsion member 986B to tie the opposing sides of the suspension system 880 together (e.g., tie the suspension assembly 882A to the suspension assembly 882B). In some examples, to tie the torsion member 986 A to the torsion member 986B, the removable end cap 914 must first be removed to provide a continuous channel through the respective suspension housings. Or, in some cases, as shown in FIGS. 19-21, one or more torsion members can extend through a common suspension housing that extends across a full lateral span of a frame (e.g., to collectively support axles on opposing lateral sides of the power machine).

[0132] In some examples, to permit movement of the suspension system 880 during use of the power machine, the frame 810 may include oblong openings 1044, which may permit movement of the axles 328 during operation of the vehicle, without risk of the axles contacting the frame 810, which may cause damage to the axle assemblies (e.g., including the motors,hydraulics, electronics, etc.). Further, to prevent over-travel of the suspension system 880, the frame may include a stop configured as a protrusion 1008 extending outward from the frame 810. In some examples, the protrusion 1008 may be configured to contract an edge 1084 of the second weldment 904 to prevent over-travel of the suspension system 880, which may risk damage to the axles, motor, etc. Further, an exterior of the protrusion 1008 may include an elastomeric (e.g., rubber) coating to absorb impacts between the edge 1084 of the second weldment 904 and the protrusion 1008.

[0133] In some examples, to mitigate the risk of deflection of the suspension system 880, a pad 1105 may be arranged on the frame 810. The pad 1105 may serve as a contact point for the mounting plate 996 of the second weldment 904, while also mitigating the risk of deflection of the suspension system. For example, during movement of the mounting plate 996 (e.g., due to a change in terrain, movement of the wheel, etc.) the mounting plate 996 may move against the surface of the pad, within a plane defined by the surface of the pad 1105 (e.g., parallel to the surface of the pad), which may reduce the risk of deflection of the suspension system 880 (and thus the wheel). In some examples, the pad 1105 may be made from a metal or metallic material in order to resist wear (e.g., during use of the power machine). Further, the pad 1105 may be positioned on a side of the mounting plate 996 that is opposite of the connection to the torsion member 986 (e.g., to assist in the mitigation of deflection of the suspension system. In some examples, the pad 1105 may be substantially rectangular in shape, but other shapes of the pad are envisioned (e.g., arcuate, etc.). Further, the pad 1105 may be sized so that an exterior surface of the mounting plate 996 is substantially parallel with the frame 810 adjacent the pad. Put differently, the thickness of the pad 1105 may be designed to align the mounting plate 996 substantially parallel with the frame (e.g., to mitigate deflection of the suspension system).

[0134] Further, in some examples, to reduce the risk of debris contacting the motor (e.g., the motor 226 built into the axle assembly) a boot 1115 may be arranged between the frame 810 and the mounting plate 996. In some cases, the boot 1115 may be made from a rubber or other elastomeric material. Further, the boot may mitigate the risk of ingress of debris (e.g., past the frame 810, through the opening 1044) into the motor 226, which may extend the service life of the motor 226.

[0135] FIG. 32 illustrates another example of a suspension system 1280 that can be used with the power machine 300 of FIG. 3 (e.g., as an alternative configuration of the suspension systems 480, 680, etc.). As will be recognized, the suspension system 1280 shares a number of components in common with and operates in a similar fashion to the examples illustrated anddescribed previously. For the sake of brevity, these common features will not be described again below in detail. Rather, previous discussion of similarly named or numbered features, unless otherwise indicated, also applies to example configurations of the suspension system 1280.

[0136] In some cases, a user may want to “lock” the suspension to prevent a change in ride height - e.g., during a grading or other operation. To facilitate this, the mounting plate 1296 of the suspension system 1280 may define a pin aperture 1302. The pin aperture 1302 may be configured to removably (selectively) receive a locking pin 1304 to lock the suspension system 1280 against vertical travel.

[0137] In some examples, the locking pin 1304 may be in the form of a fastener (e.g., a screw, bolt, nut, rod, or any other known fastener). Further, the locking pin 1304 may be configured to engage with the frame 810 via a threaded or unthreaded opening on the frame.

[0138] Thus, in some examples, to lock the suspension system 1280, an operator may position the locking pin 1304 through the pin aperture 1302 and into the corresponding opening on the frame 810. As a result, the axle(s) may be directly tied to the frame 810, so that loading from vertical forces on the mounting plate (e.g., via the axle) may be transferred to the frame 810 primarily via the pin rather than via torsional deflection of the suspension system 1280. For example, a force applied in the direction shown by arrows 1306 may pass directly from the axle(s) to the frame 810, without a reduction or redirection in force via the suspension system 1280.

[0139] In some examples, the frame 810 may include multiple apertures (represented by dashed circles) configured to receive the locking pin 1304. Thus, an operator may select a particular aperture within the frame to lock the ride height of the power machine at a desired ride height.

[0140] In some examples, during manufacturing a customer may desire a power machine 300 without the suspension system (e.g., suspension systems 880, 1280). Thus, to facilitate the ease of manufacturing as shown schematically in FIG. 32, an axle plate 1310 may be positioned on the frame 810 and then fastened to the frame via one or more fasteners. Correspondingly, the axle assembly 328 may be supported relative to the frame by (e.g., mounted directly to) the axle plate 1310. Thus, the axle assembly 328 may be connected to the frame 810 via the axle plate 1310 (or otherwise), without a suspension assembly (e.g., with the axle assembly 328 thus rigidly fixed to the frame 810). Further, if desired, the axle assembly and correspondingaxle plate 1310 may thereafter be removed and replaced with the first and second weldments 902, 904 to retrofit the power machine with a suspension system. Thus, the power machine may be modular, with a single frame 810 providing the option for both a suspension system and a suspension-less system.

[0141] Certain operations of methods according to the present disclosure, or of systems executing those methods, may be represented schematically in the figures or otherwise discussed herein. Unless otherwise specified or limited, representation in the figures of particular operations in particular spatial order may not necessarily require those operations to be executed in a particular sequence corresponding to the particular spatial order. Correspondingly, certain operations represented in the figures, or otherwise disclosed herein, can be executed in different orders than are expressly illustrated or described, as appropriate for particular implementations of the present disclosure. Further, in some examples, certain operations can be executed in parallel.

[0142] As used herein, unless otherwise limited or defined, “or” indicates a non-exclusive list of components or operations that can be present in any variety of combinations, rather than an exclusive list of components that can be present only as alternatives to each other. For example, a list of “A, B, or C” indicates options of: A; B; C; A and B; A and C; B and C; and A, B, and C. Correspondingly, the term “or” as used herein is intended to indicate exclusive alternatives only when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” For example, a list of “one of A, B, or C” indicates options of: A, but not B and C; B, but not A and C; and C, but not A and B. A list preceded by “one or more” (and variations thereon) and including “or” to separate listed elements indicates options of one or more of any or all of the listed elements. For example, the phrases “one or more of A, B, or C” and “at least one of A, B, or C” indicate options of: one or more A; one or more B; one or more C; one or more A and one or more B; one or more B and one or more C; one or more A and one or more C; and one or more of A, one or more of B, and one or more of C. Similarly, a list preceded by “a plurality of’ (and variations thereon) and including “or” to separate listed elements indicates options of multiple instances of any or all of the listed elements. For example, the phrases “a plurality of A, B, or C” and “two or more of A, B, or C” indicate options of: A and B; B and C; A and C; and A, B, and C.

[0143] Unless otherwise specified or limited, the terms “about” and “approximately,” as used herein with respect to a reference value, refer to variations from the reference value of ± 15% or less (e.g., ± 10%, ± 5%, etc.), inclusive of the endpoints of the range. Similarly, the term“substantially equal” (and the like) as used herein with respect to a reference value refers to variations from the reference value of less than ± 30% (e.g., ± 20%, ± 10%, ± 5%) inclusive. Where specified, “substantially” can indicate in particular a variation in one numerical direction relative to a reference value. For example, “substantially less” than a reference value (and the like) indicates a value that is reduced from the reference value by 30% or more, and “substantially more” than a reference value (and the like) indicates a value that is increased from the reference value by 30% or more.

[0144] As used herein in the context of a power machine, unless otherwise defined or limited, the term “lateral” refers to a direction that extends at least partly to a left or a right side of a front-to-back reference line defined by the power machine. Accordingly, for example, a lateral side wall of a cab of a power machine can be a left side wall or a right side wall of the cab, relative to a frame of reference of an operator who is within the cab or is otherwise oriented to operatively engage with controls of an operator station of the cab. Similarly, a “centerline” of a power machine refers to a reference line that extends in a front-to-back direction of a power machine, approximately half-way between opposing lateral sides of an outer spatial envelope of the power machine.

[0145] Also as used herein, unless otherwise defined or limited, the terms “inboard” and “outboard” refer to a relative relationship (e.g., a lateral distance) between one or more objects or structures and a centerline of the power machine, along a lateral side of the power machine. For example, a first structure that is inboard of a second structure is positioned laterally inward from the second structure so that a distance between the first structure and the centerline of the power machine is less than a distance between the second structure and the centerline of the power machine. Conversely, a first structure that is outboard of second structure is positioned laterally outward from the second structure so that a distance between the first structure and the centerline of the power machine is greater than a distance between the second structure and the centerline of the power machine.

[0146] Similarly, as used herein, unless otherwise defined or limited, the terms “interior” and “exterior” refers to a relative relationship (e.g., a lateral distance) between one or more structures (e.g., a sub-structure) and a centerline of a reference structure (e.g., a main structure) that extends in a front-to-back direction or between first and second ends of the reference structure. For example, an interior structure is disposed closer to a centerline of a reference structure than an exterior structure. In this regard, an outboard structure of a subassembly of a power machine may also be an exterior structure, but an exterior structure of a subassembly,relative to a centerline of the subassembly, may not necessarily be outboard of other components of the subassembly.

[0147] Unless otherwise defined or limited, two components that are described herein as “substantially aligned” are aligned along a particular reference direction (e.g., a front-to-back direction of a power machine) across more than half of a dimension of at least one the components in a direction orthogonal to the reference direction.

[0148] Also as used herein, unless otherwise limited or defined, “substantially parallel” indicates a direction that is within ± 12 degrees of a reference direction (e.g., within ± 6 degrees), inclusive. For a path that is not linear, the path can be considered to be substantially parallel to a reference direction if a straight line between end-points of the path is substantially parallel to the reference direction or a mean derivative of the path within a common reference frame as the reference direction is substantially parallel to the reference direction. Similarly, as used herein, unless otherwise limited or defined, “substantially perpendicular” indicates a direction that is within ± 12 degrees of perpendicular a reference direction (e.g., within ± 6 degrees), inclusive. For a path that is not linear, the path can be considered to be substantially perpendicular to a reference direction if a straight line between end-points of the path is substantially perpendicular to the reference direction or a mean derivative of the path within a common reference frame as the reference direction is substantially perpendicular to the reference direction.

[0149] Also as used herein, unless otherwise limited or defined, “operably supported” refers to two components that are moveably engaged together to transmit power. Similarly, “operably engaged” indicates that a first component and a second components are connected together so that the first component provides structural support to the second, relative to the first component or another structure.

[0150] Although the presently disclosed technology has been described with reference to preferred implementations, workers skilled in the art will recognize that changes may be made in form and detail without departing from the scope of the discussion.

Claims

WHAT IS CLAIMED IS:

1. A power machine comprising: a frame that includes a front frame member and rear frame member that is pivotally coupled to the front frame member at a frame joint; a power source supported by the frame; a tractive system that includes a first axle that is operably engaged with a first drive motor powered by the power source; and a suspension system that moveably supports the first axle and the first drive motor relative to the front frame member or the rear frame member.

2. The power machine of claim 1, wherein the first axle is cantilevered from the front frame member or the rear frame member by the suspension system.

3. The power machine of claim 2, wherein the suspension system further includes: a torsion member supported by the frame; and a lever member that is coupled to the torsion member at a first end and coupled to the first axle at a second end.

4. The power machine of claim 3, wherein the suspension system includes a torsion pad secured relative to the frame to resiliently respond to torsional force applied to the torsion member by movement of the lever member relative to the frame.

5. The power machine of claim 4, wherein the torsion member is at least partially housed within a suspension housing secured to the frame, and wherein the torsion pad is arranged within the suspension housing.

6. The power machine of claim 5, wherein the torsion member is held within the suspension housing via a frictional force generated by the torsion pad.

7. The power machine of claim 5, wherein the torsion member defies a rectangular crosssection, the suspension housing defines a rectangular cross-section, and the torsion member is arranged within the suspension housing at about a 45-degree offset relative to the suspension housing.

8. The power machine of claim 1, wherein the frame includes an oblong opening corresponding to the first axle, and the first drive motor extends from a suspension arm of the suspension system through the oblong opening to permit movement of the first axle relative to the frame via movement of the suspension system.

9. The power machine of claim 1, further comprising: a locking pin, the locking pin arranged between the suspension system and the frame to selectively lock movement of the first axle relative to the frame.

10. A power machine comprising: a frame that is pivotable at a frame joint; a power source supported by the frame; a tractive system that includes a first axle that is operably engaged with a first drive motor powered by the power source; and a suspension system to permit movement of the first axle relative to the frame, the suspension system including: a first torsion member supported by the frame; and a first suspension arm coupled to the first torsion member at a first end and to the first axle at a second end to permit vertical movement of the first axle relative to the first torsion member.

11. The power machine of claim 10, wherein the frame includes a front frame member and a rear frame member that is pivotally coupled to the front frame member at the frame joint; and wherein the suspension system includes: a first suspension assembly supported by the front frame member, the first suspension assembly including the first torsion member coupled to the front frame member, wherein the first suspension arm cantilevers the first axle relative to the first torsion member; and a second suspension assembly supported by the rear frame member, the second suspension assembly including a second torsion member coupled to the rear frame member, and a second suspension arm coupled to the second torsion member and to a second axle to cantilever the second axle relative to the second torsion member.

12. The power machine of claim 11, wherein, relative to a front-to-back direction of the front frame member, the first suspension arm extends forward of the first torsion member to support the first axle; and wherein, relative to a front-to-back direction of the rear frame member, the second suspension arm extends rearward of the second torsion member to support the second axle.

13. The power machine of claim 10, wherein an end portion of the first suspension arm extends past the first axle in a direction away from the first torsion member; and wherein a guide structure extending from the frame engages the end portion to limit lateral deflection of the first suspension arm.

14. The power machine of claim 10, wherein the suspension system includes a torsion pad configured to resiliency resist torsional force applied to the torsion member.

15. The power machine of claim 14, wherein the torsion member is received within a first suspension housing that is secured to and extends laterally across the frame, the torsion pad being arranged within the suspension housing to engage the torsion member.

16. The power machine of claim 15, wherein the torsion member defies a rectangular crosssection, the first suspension housing defines a rectangular cross- section, and the torsion member is arranged within the first suspension housing at a 45-degree offset relative to the first suspension housing.

17. The power machine of claim 15, further comprising: a second suspension system to permit movement of a second axle relative to the frame, the second axle being laterally opposite the first axle relative to a front-to-back direction of the power machine, the second suspension system including: a second torsion member supported by the frame; and a second suspension arm coupled to the second torsion member at a first end and to the second axle at a second end to permit vertical movement of the second axle relative to the second torsion member; wherein the second torsion member is received within a second suspension housing that is secured to and extends laterally across the frame, laterally opposite the first suspension housing, to engage a second torsion pad arranged within the second suspension housing.

18. A method of assembling a power machine, the method comprising: securing a suspension housing of a suspension assembly to one of a front frame member or a rear frame member of a frame of the power machine, the front frame member being pivotally coupled to the rear frame member at a frame joint; arranging a torsion member of the suspension assembly to extend into the suspension housing; and moveably supporting an axle of the power machine relative to the one of the front frame member or the rear frame member via a suspension arm of the suspension assembly that is secured to the torsion member.

19. The method of claim 18, further comprising: arranging a torsion pad within the suspension housing, the torsion pad engaging at least a portion of a perimeter of the torsion member to resiliently resist torsional force applied to the torsion member.

20. The method of claim 18, further comprising: securing a second suspension housing of a second suspension assembly to the other of the front frame member or the rear frame member; arranging a second torsion member of the second suspension assembly to extend into the second suspension housing; and moveably supporting a second axle of the power machine relative to the other of the front frame member or the rear frame member via a second suspension arm of the second suspension assembly that is secured to the second torsion member; wherein the suspension arm extends in a first direction from the torsion member to the axle, relative to a front-to-back axis of the power machine; and wherein the second suspension arm extends from the second torsion member to the second axle in a second direction that is opposite the first direction, relative to the front-to-back axis.

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